Abstract: An improvement in the preparation of printed circuits comprises inserting a deformable layer between the phototool or support layer, and the solder mask. The deformable layer provides a uniform, integral and relatively thin coating of solder mask over circuit components, and results in higher-quality solder joints and lower rejection rates for finished boards.
Type:
Grant
Filed:
February 22, 1990
Date of Patent:
September 22, 1992
Assignee:
Elf Atochem North America, Inc.
Inventors:
Paul L. K. Hung, John Cioffi, Mark L. Lavach
Abstract: The invention relates to a polynorbornene-based rubbery composition with improved thermal behaviour, comprising a mixture of at least 50% by weight of polynorbornene and not more than 50% by weight of another rubber, the said mixture having been vulcanized by means of effective quantity of at least one compound: ##STR1## where R.sub.1, R.sub.2 =CH.sub.n X.sub.3-n, with X=F, Cl or Br and n = integer from 0 to 2; the invention also relates to a thermoplastic composition comprising 10-90 parts by weight (pw) of at least one olefin-based crystalline polymer (A), from 90-10 pw of a mixture (B) of at least 50% by weight of polynorbornene and not more than 50% by weight of another rubber, and a sufficient quantity of plasticiser for polynorbornene to lower its glass transition temperature to the range of rubbers, the sum of (A) and of (B) being equal to 100 pw and (B) being vulcanized by means of an effective quantity of at least one compound (I).
Abstract: The invention relates to fluorinated acrylic monomers of the formula: ##STR1## in which A and W denote divalent linkages, R is a hydrogen atom or a methyl radical, R.sub.F is a perfluoroalkyl radical and Q denotes an oxygen or sulphur atom or the group--NR'--, where R' denotes a hydrogen atom or an alkyl radical. Homo- or copolymers derived from these monomers are useful for the water or oil-repellent treatment of various substrates, particularly leather.
Abstract: A process for the manufacture of high-yield pulps bleached with the aid of hydrogen peroxide in alkaline medium, which consists in subjecting the pulp to be bleached successively to:(a) a pretreatment with the aid of a sequestering agent for metal ions, followed by a washing operation,(b) a treatment with sulphite and a reducing agent which is more electronegative than the sulphite ion, which act together and in a medium of initial pH between 7 and 12.5, followed by a washing operation to remove the sulphite ions and the reducing agent, and(c) to a bleaching treatment with the aid of hydrogen peroxide in alkaline medium in the presence of a quantity of silicate of between 0% and 1%.
Abstract: This process is intended to remove at least a part of the heat produced in at least one reaction and/or purification operation involving anhydrous HF, the cooling being performed by heat exchange with a cooling fluid circulating in a circuit which comprises at least one exchange zone (9; 10; 11) presenting a risk of leakage of HF into the cooling fluid. The fluid of this kind which is employed is an aqueous solution of at least one compound chosen from (a) strong bases, (b) the salts resulting from the combination of a strong base and of an organic or inorganic acid whose pKa is >3.5, (c) the salts of amphoteric oxides with bases, (d) compounds which, in contact with water, are converted into one of the abovementioned compounds; the said cooling fluid is circulated in a closed circuit, and the operation is carried out with a cooling fluid pressure which is lower than the pressure at which the reaction and/or the purification operation is conducted.
Type:
Grant
Filed:
May 2, 1991
Date of Patent:
September 1, 1992
Assignee:
Elf Atochem S.A.
Inventors:
Daniel Cauvy, Francis Couget, Raymond Slota, Bernard Villemin
Abstract: The invention relates to a composition which is usable for the stabilization of thermoplastic resin against the effects of heat and/or light.This composition comprises a hydrotalcite, a zinc zeolite and a zinc carboxylate.It is applied, more especially, to thermoplastic resins containing halogens, and in particular to PVC.
Abstract: There is disclosed a catalyst for the liquid phase oxidation of functional groups comprising metalloporphyrins carrying anionic groups as substituents in which the metalloporphyrins are immobilized on a support which is made of a polymer containing nitrogenous groups used as a Lewis base and to a process of making the same.
Type:
Grant
Filed:
April 3, 1991
Date of Patent:
August 25, 1992
Assignees:
Societe Nationale Elf Aquitaine, Atochem
Inventors:
Bernard Meunier, Gilles Labat, Jean-Louis Seris
Abstract: A hood for coating glass articles has side walls and a top part, forming a tunnel through which hot glass articles pass; blowing and suction channels in the active part of the hood are formed to present substantial line contacts facing the ware being coated. By introducing relatively large radiating surfaces, the buildup of reaction-product crust on the interior of the apparatus is minimized.
Abstract: Polymeric flame retardants comprise halogenated aromatic compounds having acylamino functional groups which are chemically bonded to cyclic imide-containing or imide-forming polymers or copolymers. The polymeric flame retardants are prepared by the reaction of halogenated aromatics containing a reactive hydrazido group with some or all of the anhydride groups of an cyclic alpha, beta-unsaturated dicarboxylic acid anhydride polymer or copolymer to form pendant halogenated-aromatic-substituted imide or amic acid groups. In addition, polymeric film retardants are used to render thermoplastic resins less flammable under conditions which promote combustion. Novel flame retardant hydrazides are disclosed.
Abstract: Apparatus for the coating of glass containers has a series of vertical slots for applying coating chemicals to a hot glass jar with a minimal neck and shoulder area. An opposing horizontal slot exhausts spent coating material and reactants in a laminar flow. A center section provides a current of gas without chemicals parallel to the coating stream, and flowing with low velocity relative to the coating stream, but with high velocity relative to the extraneous turbulent and convection currents.
Abstract: The invention relates to the preparation of halogenated imides derived from hydrazine and halogenated dicarboxylic acid anhydride and which can be used as flameproofing agents for plastics. The condensation of hydrazine and halogenated dicarboxylic acid anhydride is carried out in an aqueous medium, at a temperature ranging from 40.degree. to 225.degree. C., with a molar ratio of anhydride/hydrazine equal to between 0.5 and 3, preferably between 1 and 2.
Type:
Grant
Filed:
July 22, 1988
Date of Patent:
August 11, 1992
Assignee:
Atochem
Inventors:
Evelyne Bonnet, Andre Gagnieur, Bernard Gurtner
Abstract: Novel thermotropic aromatic copolyesters comprise the following recurring structural units: ##STR1## and are prepared by polycondensing p-(p-hydroxyphenoxy)-benzoic acid with an aromatic or cycloaliphatic diacid, a diphenol and, optionally, p-hydroxybenzoic acid.
Abstract: A hardenable copolymer containing copolymerization molecular constituents from a fluorinated monomer and an allylic compound, characterized in that:(a) the fluorinated monomer molecular constituents originate from the combination of tetrafluoroethylene and chlorotrifluoretyhylene,(b) the molecular constituents from the allylic compound originate from an allylic polyol of formula: ##STR1## in which R.sub.1 is H or CH.sub.2 OH, R.sub.2 is OH or CH.sub.2 OH, R.sub.3 is CH.sub.3 or OH, with the condition that R.sub.1 and R.sub.3 cannot be simultaneously H and CH.sub.3, and that it also contains(c) copolymerization molecular constituents from a vinylic ether of formula:CH.sub.2 .dbd.CH--O--Rin which R is a linear or branched chain alkyl radical with 2 to 13 carbon atoms, and the process of making such copolymers and paints and varnishes containing the same.
Abstract: An integrated apparatus and a process for precipitation and charcoal absorption of pesticide residues in agriculatural waste water solutions are disclosed.
Abstract: A hardenable copolymer containing copolymerization molecular constituents from a fluorinated monomer and from an allylic monomer, characterized in that:(a) the fluorinated monomer molecular constituents orignate from the combination of tetrafluoroethylene and at least one other fluorinated monomer selected from chlorotrifluorethylene, vinylidene fluoride, or a mixture thereof,(b) the allylic monomer is an allylic polyol of formula: ##STR1## in which R.sub.1 is H or CH.sub.2 OH, R.sub.2 is OH or CH.sub.2 OH, andR.sub.3 is CH.sub.3 or OH, with the proviso that R.sub.1 and R.sub.3 cannot be simultaneously H and CH.sub.3, and that it contains:(c) molecular constituents from an allylic or acryllic monomer with a fluorocarbon chain of formula: ##STR2## in which n has a value of 3 to 12, R.sub.4 is H or CH.sub.3, and ##STR3## and the process of making such copolymer and paints and varnishes containing the same.
Abstract: The polycondensation disrupting effects of the impurities in an impure N-dichlorophosphoryltrichlorophosphazene, P.sub.2 NOCl.sub.5, or oligomer thereof, are avoided by polycondensing such impure P.sub.2 NOCl.sub.5 into a high molecular weight uncrosslinked poly(dichlorophosphazene) in the presence of an effective impurity-inhibiting, polymerization-controlling amount of phosphorous pentachloride, PCl.sub.5.
Type:
Grant
Filed:
October 22, 1990
Date of Patent:
July 21, 1992
Assignee:
Atochem
Inventors:
Roger de Jaeger, Ghislaine D'Halluin, Guy Pagniez, Philippe Potin
Abstract: Stabilized polyurethanes, polyureas and polyurethane-polyurea polymers having hindered amine light stabilizers (HALS) bonded thereto by means of a hydrazide functionality attached to the HALS are provided. The synergistic effect of a second amide functional group in the HALS-hydrazide provides improved photostabilization efficiency as compared to HALS-hydrazides of the prior art.
Abstract: The process for the separation of isomeric dichlorotoluenes, comprising the steps of:(a) passing a mixture containing isomeric dichlorotoluenes over a zeolite of the ZSM5 type having the composition (expressed in molar ratios) of (0.9+0.2) M.sub.2/n O:Al.sub.2 O.sub.3 : (10-100) SiO.sub.2 : z H.sub.2 O in which M is at least one cation selected from H, an alkali metal, an alkaline earth metal or a tetraalkylammonium cation; n is the valency of M; and z is between 0 and 40:(b) separating the non-adsorbed dichlorotoluenes;(c) contacting the zeolite containing the adsorbed isomers with an eluent; and(d) separating the isomers from the eluent.
Type:
Grant
Filed:
November 9, 1990
Date of Patent:
June 30, 1992
Assignee:
Atochem
Inventors:
Sergio Carra, Renato Paludetto, Guiseppe Storti, Massimo Morbidelli, Bernard Gurtner, Raymond Commandeur