Abstract: The invention relates to a process for preparing aromatic diisocyanates by reaction of phosgene with diamines in the gas phase, in which the reaction is carried out in a reaction zone at moderate pressures, i.e. the pressure in this reaction zone is more than 3 bar and less than 20 bar.

Abstract: The present disclosure relates, according to some embodiments, to apparatus, systems, and/or methods for fractionating a feed mixture comprising, for example, one or more isocyanates, light components, solvents and/or heavier components. In some embodiments, fractionating an isocyanate feed mixture may comprise distilling the feed mixture in a non-adiabatic fractionating apparatus comprising a prefractionating section and/or column and a main section and/or column, which comprises a rectification section, a side section, and a stripping section. For example, isocyanates may be separated from light component(s), solvent(s) and/or heavier component(s). A fractionating apparatus may be configured and arranged, in some embodiments, as a dividing wall column. According to some embodiments of the disclosure, apparatus, systems, and/or methods may be energy efficient and/or may have a broad operating range.

Abstract: A polyol prepolymer having at least one urethane group is disclosed. The polyol preopolymer is a reaction product of at least one isocyanate and a polyol blend, where the polyol blend includes at least one conventional petroleum-based polyol and at least one natural oil based polyol. The polyol prepolymer may be used in producing flexible polyurethane foams.

Abstract: Dendritic or hyperbranched polyurethanes are prepared by 1) reacting diols or polyols having at least one tertiary nitrogen atom and at least two hydroxyl groups of differing reactivity toward isocyanate groups with diisocyanates or polyisocyanates to form an addition product, with the diols or polyols and diisocyanates or polyisocyanates being selected so that the addition product has, on average, one isocyanate group and more than one hydroxyl group or one hydroxyl group and more than one isocyanate group, 2) converting the addition product from step 1) into a polyaddition product by intermolecular reaction of the hydroxyl groups with the isocyanate groups, and with a reaction with a compound containing at least two hydroxyl groups, mercapto groups, amino groups or isocyanate groups also being able to be carried out first, 3) if desired reacting the polyaddition product from step 2) with a compound containing at least two hydroxyl groups, mercapto groups, amino groups or isocyanate groups.

Abstract: Methods comprising: providing a migrate-sensitive substrate having a surface to be bonded; providing an adhesive formulation comprising an isocyanate-terminated polyurethane prepolymer containing one or more tertiary amino groups; and forming a migrate-free adhesive bond between the surface of the migrate-sensitive substrate and a second surface; as well as adhesive formulations comprising an isocyanate-terminated polyurethane prepolymer containing one or more tertiary amino groups; and wound closure systems comprising such an adhesive formulation.

Abstract: The invention relates to the use of special isocyanate-terminated polyurethane prepolymers in adhesive formulations. Said adhesive formulations can be used in applications in which it is important to prevent or minimize migration of adhesive components when the adhesive layer is in direct or indirect contact with substrates that are sensitive thereto.

Abstract: The present invention relates to salts of 2-iodo-N-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)carbamoyl]benzenesulfonamide, to processes for their preparation and to their use as herbicides, in particular as herbicides for the selective control of unwanted harmful plants in crops of useful plants, permanent crops or on non-crop land, and also as plant growth regulators, on their own or with safeners and/or in combination with other herbicides, to their use for controlling unwanted harmful plants (such as, for example, broad-leaved/weed grasses) in specific crop plants or as crop protection regulators, for simultaneous and/or sequential application, either as a readymix or as a tank mix.

Abstract: A prepolymer or elastomer is the reaction product of reactants (a) at least one polyester polyol or fatty acid derived polyol which is the reaction product of at least one initiator and a mixture of fatty acids or derivatives of fatty acids comprising at least about 45 weight percent monounsaturated fatty acids or derivatives thereof, (b) optionally, at least one polyol which is different from the polyol of (a); and (c) at least one isocyanate compound (herein after isocyanate) having an average of at least about 1.8 isocyanate groups per molecule. A process comprises admixing reactants (a) at least one polyol composition comprising the fatty acid derived polyol which is the reaction product of at least one initiator and a mixture of fatty acids or derivatives of fatty acids comprising at least about any of 45 weight percent monounsaturated fatty acids or derivatives thereof; and (b) at least one isocyanate having an average functionality of at least about 1.

Abstract: The present invention is to the preparation and application of isocyanate based polymers, particularly polyurea elastomeric polymers. By incorporating polybutadiene with a natural oil based polyol in a thermoplastic system, particularly in the formation of a prepolymer the produced elastomer display good chemical resistance. Such prepolymers are an isocyanate terminate prepolymer wherein the polyol composition for the production of the prepolymer comprises a polybutadiene polyol and a natural oil based polyol.

Abstract: A method of making a polyurethane foam from a mixture of isocyanate modified polyol and foam-forming ingredients, wherein the isocyanate modified polyol is made by reacting at least one polyol with at least one multifunctional isocyanate, wherein the isocyanate modified polyol is a non-foamed polyol polymer having available OH groups, wherein the foam forming ingredients comprise at least a multifunctional isocyanate and a foaming agent, preferably water, and characterised in that (i) the at least one polyol from which the isocyanate modified polyol is made comprises at least one lipid-based polyol which has undergone reaction with the isocyanate in the presence of a PU gelation catalyst, and/or (ii) the isocyanate modified polyol is mixed with a lipid-based polyol prior to, or at the same time as, foaming.

Abstract: The invention relates to binder-free spot blender compositions for one- and two-component clearcoat materials comprising at least one isocyanate compound, to processes for producing them, and to their use in automotive refinish.

Abstract: The disclosure relates to biocompatible components useful for forming compositions for use as medical/surgical synthetic adhesives and sealants. Biocompatible components of the present disclosure may include a polymeric polyol core, which may be treated with a nitroaryl compound to form a nitro ester. The resulting nitro ester groups may be reduced to form amino groups which, in turn, may be treated to form isocyanate groups. The resulting isocyanate may then be reacted with a second component to form adhesive and/or sealant compositions.

Abstract: Absorbable polyurethanes, polyamides and polyester urethanes prepared from at least one compound selected from: or the diamines and diisocyanates thereof, wherein each X represents a member independently selected from —CH2COO— (glycolic acid moiety), —CH(CH3)COO— (lactic acid moiety), —CH2CH2OCH2COO— (dioxanone), —CH2CH2CH2CH2CH2COO— (caprolactone moiety), —(CH2)yCOO— where y is one of the numbers 2, 3, 4 or 6-24 inclusive, and —(CH2CH2O)z?CH2COO— where z? is an integer between 2 and 24, inclusive; each Y represents a member independently selected from —COCH2O— (glycolic ester moiety), —COCH(CH3)O— (lactic ester moiety), —COCH2OCH2CH2O— (dioxanone ester), —COCH2CH2CH2CH2CH2O— (caprolactone ester), —CO(CH2)mO— where m is an integer between 2, 3, 4 or 6-24 inclusive, —COCH2O(CH2CH2O)n— where n is an integer between 2 and 24, inclusive; R? is hydrogen, benzyl or an alkyl group, the alkyl group being either straight-chained or branched; p is an integer between 1 and 4, inclusive; and Rn represents one or more

Abstract: Microcellular polyurethane flexible foams having densities no greater than 0.3 g/cc which are suitable for use as lightweight shoe sole components are produced with carbon dioxide in an amount such that the polyurethane-forming mixture has a free rise density of from about 0.03 to about 0.3 g/cc. At least a portion of that carbon dioxide is dissolved as a gas into one or both of the reaction components. The amount of dissolved carbon dioxide must be such that the froth density of the isocyanate and/or isocyanate-reactive component(s) in which the carbon dioxide is dissolved will be from about 0.1 to about 0.8 g/cc. Additional carbon dioxide may be formed by the reaction of water and isocyanate during the polyurethane-forming reaction but the total amount of CO2 present should be controlled to ensure that the polyurethane-forming mixture has a free rise density of from about 0.03 to 0.3 g/cc.

Abstract: A microcellular polyurethane obtainable by reacting a polyisocyanate, a polyester formed from a dimer fatty acid and/or dimer fatty diol, and a chain extender. The foam is particularly suitable for use as a component of shoe soles.

Abstract: The present invention relates in a first consideration to aldimines of formula (I). Said aldimines are particularly suitable as latent hardeners in curable compositions, particularly compositions comprising one or two-component isocyanate groups. Due to the presence of the reactive group, they can be converted to compounds of the formulas (X) and (XII) comprising aldimine groups, implementing a further consideration of the present invention. The aldimines, or the compounds comprising aldimine groups, can be used primarily in adhesive and sealant materials, but also in coatings, and can be produced easily from readily available source materials, and have good thermal stability. The tertiary amino group thereof has a surprisingly low alkalinity and can in some cases have a catalytic effect in chemical reaction systems.

Abstract: The invention relates to a multi-stage process for the continuous, phosgene-free preparation of (cyclo)aliphatic diisocyanates that comprises the conversion of (cyclo)aliphatic diamines into the corresponding (cyclo)alkylene biscarbamates and the thermal cleaving of the latter into the (cyclo)alkylene diisocyanates and alcohol. The urea used in accordance with the invention and also the urea employed for the preparation of urea equivalents (e.g. alkyl carbonates, alkyl carbamates) as a possible precursor for the synthesis of the (cyclo)aliphatic biscarbamates is unconditioned.

Abstract: The present invention relates to dialdimines of the formula (I) and emulsions and uses thereof. In particular, they can be used for the preparation of pasty curing agent or accelerator components for polymers having isocyanate groups, which lead to very high early strength, which have good flow behaviour on pumping and which can be formulated without VOC solvents, in particular without N-alkylpyrrolidones. These components can be homogeneously or inhomogeneously mixed in an outstanding manner, in particular in a laminar manner, with components which contain polyurethane polymers having isocyanate groups, the two-component compositions thus obtained curing rapidly, having extremely high early strength and remaining without annoying weaknesses.

Abstract: The invention relates to a continuous process for preparing radiation-curable prepolymers containing urethane groups, more particularly urethane acrylates.

Abstract: Modified stable polyisocyanates are described having at least one isocyanate function modified by a group having cross-linking functionality.

Abstract: The present invention provides products of isocyanate functional material(s) and compound(s) selected from the group of compounds represented by structural Formula (I): wherein X, Y and R1 are as described herein, use of such compounds as anaerobic cure accelerators, and compositions including such compounds.

Abstract: In accordance with an exemplary embodiment of the present invention, an optically clear polyurethane/polyurea polymer may be prepared by reacting a cycloaliphatic diisocyanate with polyesters, polyethers, and polycarbonates which may comprise hydroxyl groups and/or primary amine groups. This reaction may be carried out using 0.5 to 0.9 equivalents of the hydroxyl/amine groups followed by the reaction of 0.1 to 0.5 equivalents of water. The glycol, amine, and water may then be reacted with a cycloaliphatic diisocyanate in a ratio of about 1.77 to about 3.5 NCO for each OH, HOH, NH2. The resulting prepolymer may then be reacted with an aromatic diamine curing agent such as diethyltoluene diamine in an equivalent ratio of about 0.85 NH2/1.0 NCO to about 1.1 NH2/1.0 NCO, and in one embodiment, from about 0.90 NH2/1.0 NCO to 0.98 NH2/1.0 NCO. In one embodiment, 0.2 to 0.3 comprises the range of water equivalents for the water diisocyanate reaction.

Abstract: The present invention provides a monomer composition comprising an aromatic halosulfonyl isocyanate having structure I wherein “m” is an integer from 2 to 5; “n” is an integer from 1 to 5; Ar is a C3-C40 aromatic radical which is free of aliphatic carbon-hydrogen bonds; and X is halogen. The monomer compositions comprising aromatic halosulfonyl isocyanate I are useful in the preparation of polymeric materials useful as membranes.

Abstract: The invention relates to a novel process for conditioning isocyanates. The purpose of conditioning of isocyanates or of mixtures of isocyanates is to remove organophosphorus components in a suitable manner such that the organophosphorus compounds no longer interfere with processing of the isocyanates.

Abstract: Isocyanates are prepared by reacting primary amines with phosgene in a reactor by a process in which a reaction discharge is present in the form of a suspension which contains the isocyanate to be prepared, as a liquid, and carbamyl chlorides as a solid, and the suspension is worked up in a film evaporator, and this process is carried out in a production plant.

Abstract: There are provided a novel ethylenically unsaturated group-containing isocyanate compound, a process for producing the same, and a reactive monomer produced from the isocyanate compound, a reactive polymer and its use. The ethylenically unsaturated group-containing isocyanate compound according to the present invention is represented by formula (I).

Abstract: The present invention concerns shape memory composites, methods of preparing same and the use of these composites, for example, for products prepared by injection moulding techniques or coating applications.

Abstract: It is an object of the present invention to provide an isocyanate group-terminated urethane prepolymer which has a low viscosity at melting and a process for producing the same, and an adhesive which comprises the urethane prepolymer and has such good workability that the adhesive in a molten state can be easily applied to substrates. The invention relates to a process for producing an isocyanate group-terminated urethane prepolymer which comprises reacting a polyol with a polyisocyanate compound, wherein the polyols comprise 10 to 60% by mass of a polyester polyol and 90 to 40% by mass of a polycarbonate polyol and a sebacic acid-derived polyester polyol which is a polycondensate of sebacic acid with a diol compound accounts for 50 to 100% by mass of the polyester polyol and wherein the polyisocyanate compound and the polyols are reacted in such amounts that the ratio (by mol) of the isocyanate group/hydroxyl group is 1.2 to 3.2.

Abstract: A prepolymer having an NCO content of less than 10%, based on the reaction of (a) diisocyanate with (b) polyether alcohol, the (b) polyether alcohol comprising (b1) and (b2) and/or (b3) with the following meanings for (b1), (b2) and (b3): (b1) polytetrahydrofuran having a molecular weight of from 1800 to 2100 g/mol and (b2) polyether alcohol having a molecular weight of from 500 to 7000 g/mol, based on ethylene oxide and/or propylene oxide, and/or (b3) polytetrahydrofuran having a molecular weight of from 800 to 1200 g/mol.

Abstract: A process for preparing fluorochemical monoisocyanates comprises reacting at least one fluorochemical alcohol represented by the formula CnF2n+1SO2NCH3(CH2)mOH, wherein n=2 to 5, and m=2 to 4, with 4,4?-diphenylmethane diisocyanate (MDI) in a solvent in which the resulting fluorochemical monoisocyanate is not soluble; wherein the molar ratio of fluorochemical alcohol:MDI is from about 1:1 to about 1:2.5.

Abstract: High-functionality polyisocyanates are prepared by a process which comprises (i) preparation of an addition product (A) which contains one group which is reactive toward isocyanate and at least two isocyanate groups by reacting (a) a diisocyanate or polyisocyanate I with (b1) compounds having at least three groups which are reactive toward isocyanate or (b2) compounds containing two groups which are reactive toward isocyanate or mixtures of (b1) and (b2), where at least one of the components (a) or (b) has functional groups having differing reactivities toward the functional groups of the other component and the reaction ratio is selected so that the addition product (A) contains an average of one group which is reactive toward isocyanate, (ii) if desired, intermolecular addition reaction of the addition product (A) to form a polyaddition product (P) containing an average of one group which is reactive toward isocyanate and an average of more than two isocyanate groups, and (iii) reaction of the addition

Abstract: The present invention concerns a process for producing low-viscosity polyisocyanates or secondary products thereof, which carry activated, radiation-curable double bonds and can optionally also cure thermally, and low-viscosity polyisocyanate mixtures or secondary products thereof and their use in coating compounds.

Abstract: A process for continuous phosgene-free preparation of cycloaliphatic diisocyanates.

Abstract: A method is described for preparing a tricondensate polyfunctional isocyanate composition, preferably having at least an isocyanurate and/or biuret group, which includes adding to a tricondensate polyfunctional isocyanate, or a mixture of different tricondensate polyfunctional isocyantes, obtained by (cyclo)condensation, in particular (cyclo)trimerization of one or several identical or different isocyanate monomers and optionally of another monomer, an allophanate of one or several identical or different isocyanates, or a mixture of different allophanates. The isocyanates or isocyanate monomer mixtures used for preparing the polyfunctional isocyanate(s) may be identical to or different from the isocyanate(s) or isocyanate mixture used for preparing the allophanate(s).

Abstract: A polyisocyanate composition comprising an allophanate group, which is obtained from an aliphatic diisocyanate(s), wherein in a state substantially free of a solvent and the aliphatic diisocyanate(s), (i) the content of components having a molecular weight of 700 or less is 20-60 weight %, (ii) the ratio of weight average molecular weight to number average molecular weight is 1.20-5.00, (iii) the ratio of viscosity (unit: mPa·s) of the polyisocyanate composition at 25° C. to the number average number of functional groups of isocyanate groups is represented by the following expression: viscosity(mPa·s)/number average number of functional groups?240.

Abstract: The present invention relates to a process for the preparation of di- and polyamines of the diphenylmethane series, and to the preparation of di- and poly-isocyanates of the diphenylmethane series from these di- and poly-amines. The di- and poly-amines of the diphenylmethane series are prepared by the reaction of aniline and formaldehyde in the presence of hydrochloric acid. In with the present invention, the hydrochloric acid employed contains less than 0.001 wt. % of metal ions which are divalent and/or more than divalent.

Abstract: The present invention relates to novel blocked, elimination-free polyurethane (PUR) crosslinking agents, to a process for their preparation and to their use as starting components for the production of polyurethane plastics, especially as crosslinking agents for thermally crosslinkable powder coatings.

Abstract: Polyurethane compositions are produced in a two-stage method. In a first step, a diol component with a molecular weight of less than 2000 is reacted with a monomeric diisocyanate with a molecular weight of less than 500 and the unreacted monomeric diisocyanate is removed from this reaction product. In a second step, the resulting high-molecular diisocyanate is reacted with a polyol to produce a reactive prepolymer with isocyanate and groups. The addition of polyisocyanates which are capable of migration and which have a substantially lower vapor pressure than diphenylmethanediisocyanate, improves the addition behavior of the invention polyurethane compositions. Reactive polyurethane compositions of this type are suitable for using as binding agents for reactive one or two component adhesives/sealants, which may optionally contain solvents. These compositions are also suitable for producing reactive hot melt adhesives when suitable polyols are selected.

Abstract: Foundry cores and molds for casting metals are prepared by forming a binder comprising a polyol, an isocyanato urethane polymer and a urethane catalyst. The binder additives and resin formulations of the invention are especially useful for casting non-ferrous metals, for example, the casting of aluminum, magnesium and other lightweight metals. The cores and molds produced for casting aluminum and other lightweight metals exhibit excellent shakeout while retaining other desirable core and mold properties.

Abstract: A polyol composition having a number average molecular weight of from about 1,000 to about 3,000 Daltons is made up of (1) at least 60% by weight of a low monol polyoxypropylene polyol having a number average molecular weight of from about 2,000 to 12,000 Da and a degree of unsaturation less than or equal to 0.02 meq/g and (2) no more than 40% by weight of a polyol having a number average molecular weight of from about 400 to about 1,000 Da and a polydispersity index greater than 1.1. This polyol composition is reacted with a diisocyanate, a polyisocyanate, an isocyanate-terminated prepolymer or an isocyanate-terminated quasi-prepolymer to produce polyurethane elastomers having good physical and mechanical properties. Any of the known processes for producing polyurethane elastomers, including one-shot processes, may be used to produce elastomers in accordance with the present invention.

Abstract: A process for preparing polyisocyanate prepolymers containing allophanate structural units that includes reacting a) one or more polyisocyanates with b) one or more polyetherpolyols containing less than or equal to 0.02 milliequivalent of unsaturated end groups per gram of polyol and having a polydispersity of from 1.0 to 1.5 and/or an OH functionality of greater than or equal to 1.9 ?to provide an NCO-functional polyurethane prepolymer containing urethane groups that are partly or fully allophanatized by further reaction with c) polyisocyanates, which may be different from those from a), and d) catalysts and optionally adding e) acidic additives before, during and/or after the allophanatization. The polyisocyanate prepolymers can be used to produce coatings, adhesive bonds and/or seals. The coatings include one or more of the polyisocyanate prepolymers, and at least one diol or polyol and/or at least one linear and/or cyclic, aliphatic, araliphatic and/or aromatic diamine or polyamine.

Abstract: Process for preparing organic isocyanates, which comprises the steps (a) making available a first partial amount of chlorine, with the chlorine of this first partial amount having a content of free and bound bromine and iodine of <400 ppm; (b) making available a second partial amount of chlorine; (c) reacting the first and second partial amounts of chlorine with carbon monoxide to form phosgene; (d) reacting the phosgene from step (c) with one or more primary amines to form the corresponding isocyanates and hydrogen chloride; (e) separating off and, if necessary, purifying the isocyanates formed in step (d); (f) separating off and, if necessary, purifying the hydrogen chloride formed in step (d); (g) catalytically oxidizing at least part of the hydrogen chloride separated off in step (e) by means of oxygen to form chlorine; (h) separating off the chlorine formed in step (g) and using at least a partial amount of the chlorine which has been separated off as second partial amount of chlorine in step (b).

Abstract: Compounds of the formula 1 OCN—R1—NHCOX—R2—(Y)n??(1), where X is a covalent bond to R2 or is O, S or NR3, Y is a hydrogen atom or a free functional group and n is an integer from 1 to 20, can be used for functionalizing or modifying compounds or solid surfaces which have at least one group which is reactive toward isocyanate.

Abstract: Polyurethanes or polyurethane-ureas prepared from: (a) polytrimethylene ether glycol having a number average molecular weight in the range of about 1,000 to about 4,000 and unsaturated end groups in the range of about 0.003 to about 0.015 meq/g; (b) diisocyanate; and (c) diol or diamine chain extender; and their manufacture, intermediates and use.

Abstract: The present invention relates to a process for preparing (cyclo)aliphatic diisocyanates and triisocyanates corresponding to the formula R—(NCO)n??(I), wherein R represents a (cyclo)aliphatic hydrocarbon group having up to 15 carbon atoms, provided that there are at least two carbon atoms between two nitrogens, n represents the number 2 or 3, by a) separately heating phosgene and a diamine or triamine corresponding to the formula R—(NH2)n??(II), ?to a temperature of 200° C. to 600° C., wherein the amine may optionally be diluted with an inert gas or with the vapors of an inert solvent, b) optionally passing the reactants over torque-producing baffles and c) continuously reacting phosgene and the amine in the gas phase in a reaction chamber without moving parts and with constrictions of the walls in the region of the reaction zone.

Abstract: The invention relates to liquid stable MDI prepolymers and curative systems which are suitable for room temperature casting and which yield high performance low-shrinkage urethane elastomers upon room-temperature curing, the prepolymer and curative components, the elastomers themselves, and separately packaged prepolymer component and its complementary curative component provided as a single unit or kit.

Abstract: Disclosed is a polyether polyurethane comprising (A) at least one polyisocyanate having two or more isocyanate groups, which is selected from the group consisting of an aromatic polyisocyanate and an aliphatic polyisocyanate; (B) a polyoxytetramethylene glycol (PTMG) having a number average molecular weight of from 500 to 4,000, a molecular weight distribution (Mw/Mn) of 1.75 or less, and a content of high molecular weight PTMG molecules of 10% by weight or less; and (C) at least one chain extender selected from the group consisting of a C2-C10 polyol having two or more hydroxyl groups and a C2-C10 polyamine having two or more amino groups. Also disclosed is a urethane prepolymer which comprises the above-mentioned components (A) and (B) and which has terminal isocyanate groups.

Abstract: The present invention relates to novel blocked, elimination-free polyurethane (PUR) crosslinking agents, to a process for their preparation and to their use as starting components for the production of polyurethane plastics, especially as crosslinking agents for thermally crosslinkable powder coatings.

Abstract: The present invention relates to novel aromatic isocyanates obtained by partially hydrogenating naphthalene as well as the processes for preparing the same, and to their use as an isocyanate component in the production of polyurethanes.

Abstract: A self-emulsifiable polyisocyanate with high functionality, having the average number of functional groups in 4.3 or more and a viscosity of 8,000 mPa·s (at 25° C.) or less, which is obtained by subjecting a modified polyisocyanate containing allophanate bonds and a poly(oxyalkylene)glycol monoalkyl ether (e) having oxyethylene bonds in a total amount of 30 mole % or more in its molecule to a urethanization reaction, said modified polyisocyanate being obtained by reacting a polyol (a) having the average number of functional groups in an amount of 2 or more with an organic polyisocyanate (b) in the presence of an allophanate-forming catalyst (c) comprising a zirconium carboxylate; and a process for producing the same.

Abstract: Alignment in X-ray lithography is generally effected in such a manner that the surface of a target mark for alignment formed on a wafer is illuminated with light for alignment through an X-ray mask, and the position of the wafer is detected from the reflected light. On the basis of the finding that the reflected light from the mask, particularly from an absorber formed thereon, greatly degrades the precision and reliability in measurement, the present invention provides a pattern transfer mask provided with a thin film which lowers the reflection factor of the mask the thin film having a thickness set a .lambda./4n (.lambda.:the wavelength of the light for alignment; n: an integer) or an odd-number multiple thereof. Thus, it is advantageously possible to overcome the above-described lowering of precision and reliablity.