Abstract: Photovoltaic cells which comprise a back plane comprising a polyester film and an adhesive coating derived from an ethylene vinyl acetate copolymer and an oxazoline crosslinking agent and methods for forming the same are described.

Abstract: The present invention aims to provide an adhesive tape excellent in resistance against sebum to be able to maintain its adhesive force even when applied to a part frequently touched with human hands, and an adhesive tape for fixing electronic device component and a transparent adhesive tape for optical use each provided with the adhesive tape. The present invention relates to an adhesive tape including an adhesive layer containing an acrylic adhesive, the adhesive layer having a swelling ratio of 100% or more and 130% or less after immersion in oleic acid under the conditions of a temperature of 60° C. and a humidity of 90% for 24 hours.

Abstract: Ethylene-vinyl alcohol copolymer composition pellets comprise: an ethylene-vinyl alcohol copolymer; a boron compound; and a predetermined amount of at least one fisheye-suppressing component, wherein pellet surface portions of the ethylene-vinyl alcohol copolymer composition pellets have a boron compound content of not higher than 1.7 ppm on a boron basis based on the weight of the pellets. The ethylene-vinyl alcohol copolymer composition pellets are capable of suppressing occurrence of fisheyes even if being used for formation of a single-layer ethylene-vinyl alcohol copolymer film.

Abstract: An ethylene-based polymer formed from reacting at least the following: ethylene and at least one asymmetrical polyene, and wherein the reaction takes place in the presence of at least one free-radical initiator; and wherein the at least one asymmetrical polyene is selected from Structure A, as described herein; Structure B, as described herein; or a combination of Structure A and Structure B.

Abstract: An esterification method of a copolymer is disclosed. The esterification method includes the steps of: (A) mixing a copolymer having a carboxylic acid group, an alcohol or an aminoalcohol compound, a catalyst of formula (I), and a first solvent to obtain a first mixture; (B) reacting the first mixture at a predetermined temperature to obtain a second mixture; and (C) adding the second mixture into a second solvent; wherein the catalyst of formula (I) is shown below: [M(O)a]m+Xbn???(I) wherein M, X, a, b, in, and n are defined in the specification.

Abstract: An additive for oil well cement contains a vinyl alcohol polymer and has good fluid loss reducing performance. The additive for oil well cement is a saponified product of a copolymer of a vinyl ester monomer and a multifunctional monomer, and has a degree of saponification of 70 to 95 mol % and a viscosity-average degree of polymerization of 1000 to 10000.

Abstract: Ethylene-vinyl alcohol copolymer composition pellets comprise: an ethylene-vinyl alcohol copolymer, a conjugated polyene, and a predetermined amount of at least one fisheye-suppressing component; wherein pellet surface portions of the ethylene-vinyl alcohol copolymer composition pellets have a conjugated polyene content of not lower than 30 ppb based on the weight of the pellets. Such ethylene-vinyl alcohol copolymer composition pellets are capable of reliably suppressing occurrence of minute fisheyes having a diameter of 200 ?m or smaller.

Abstract: Provided is a polymer having a sharp melting peak and allowing easy adjustment of the melting peak temperature. Specifically provided is a polymer having two or more kinds of constitutional units containing an alkyl group having 14 or more and 30 or less carbon atoms, wherein the proportions of the number of the two or more kinds of constitutional units containing an alkyl group having 14 or more and 30 or less carbon atoms are each 20% or more, with respect to 100% of the total number of all constitutional units containing an alkyl group having 14 or more and 30 or less carbon atoms. An enthalpy of fusion of the polymer observed within a temperature range of 10° C. or higher and lower than 60° C. in differential scanning calorimetry is 30 J/g or more.

Abstract: Provided is a vinyl alcohol polymer having good fluid loss reducing performance. The vinyl alcohol polymer is a saponified product of a copolymer of a vinyl ester monomer and a multifunctional monomer, and has a degree of saponification of 70 to 95 mol % and a viscosity-average degree of polymerization of 1000 to 10000.

Abstract: Provided is a vinyl alcohol-based copolymer, obtained by saponifying a copolymer of vinyl acetate and a polyfunctional monomer, wherein the polyfunctional monomer contains two or more ethylenic double bonds in its molecule, the vinyl alcohol-based copolymer has a side chain containing an ethylenic double bond and a molar ratio (d) of the ethylenic double bond to a total of vinyl alcohol units and vinyl acetate units is from 0.05/100 to 2/100, and the vinyl alcohol-based copolymer is water soluble.

Abstract: The present invention is characterized by being a polyvinyl alcohol powder having an average particle diameter of 100 to 2000 ?m as measured by optical microscopic observation at a humidity of 65% RH and a temperature of 25° C., having a bulk specific gravity (g/ml) of a portion ranging from 500 to 1000 ?m in particle diameter of more than 0.60 and less than 0.80, and having a content of the portion ranging from 500 to 1000 ?m in particle diameter of 35 to 70% by mass. Accordingly, a polyvinyl alcohol powder is provided, that is good in anti-scattering property, superior in solubility in preparing an aqueous solution from the powder, and capable of reducing transport costs due to its large specific gravity.

Abstract: Provided is a vinyl alcohol-based copolymer, obtained by saponifying a copolymer of vinyl acetate and a polyfunctional monomer, wherein the polyfunctional monomer contains two or more ethylenic double bonds in its molecule, the vinyl alcohol-based copolymer has a side chain containing an ethylenic double bond and a molar ratio (d) of the ethylenic double bond to a total of vinyl alcohol units and vinyl acetate units is from 0.05/100 to 2/100, and the vinyl alcohol-based copolymer is water soluble.

Abstract: A transparent ABS resin composition of the present invention comprises: an acrylonitrile-butadiene-styrene graft (g-ABS) copolymer which is copolymerized by mixture of acrylate based monomer, styrene based monomer, and acrylonitrile based monomer (a2) on butadiene based rubber polymer (a1); and (B) a styrene-acrylonitrile based copolymer, satisfies a relation denoted by Equation 1 and Equation 2 below, and has excellent impact resistance, scratch resistance, and transparency: 0?|X?Y|?0.005??(Equation 1) 0?|X?Z|?0.005??(Equation 2) In the Equations, X is refractive index of the acrylonitrile-butadiene-styrene graft (g-ABS) copolymer, Y is refractive index of the butadiene based rubber polymer (a1), and Z is refractive index of the styrene-acrylonitrile based copolymer (B).

Abstract: The present invention relates to a preparation method of a superabsorbent polymer, and specifically to a method of preparing a superabsorbent polymer including the steps of: preparing a hydrous gel phase polymer by thermal polymerizing or photo-polymerizing a monomer composition including a water-soluble ethylene-based unsaturated monomer and a polymerization initiator; drying the hydrous gel phase polymer; milling the dried polymer; classifying the milled hydrous gel phase polymer into two or more grades by particle size; adding a surface cross-linking agent to each hydrous gel phase polymer classified into two or more grades; and carrying out a surface cross-linking reaction of the hydrous gel phase polymer to which the surface cross-linking agent is added.

Abstract: An ionomer has an ABA-type triblock structure, wherein an A-block is an ionic polymer block including a structural unit having a general formula (i) expressed as follows: —(CH2—CR1(COOM1/y)- where R1 is one of a methyl group and hydrogen, M is one of metal, NH4, organic ammonium and imidazolium, and y is a valence of an M ion, and a B-block is a nonionic polymer block selected from a group consisting of an olefin (co) polymer block, a vinyl (co) polymer block, a diene (co) polymer block, a polyester resin block and a polycarbonate resin block.

Abstract: The present invention relates to a method of preparing a superabsorbent polymer, including the steps of: preparing a hydrous gel phase polymer by thermal polymerizing or photo-polymerizing a monomer composition including a water-soluble ethylene-based unsaturated monomer and a polymerization initiator; drying the hydrous gel phase polymer; milling the dried polymer; adding a surface cross-linking agent to the milled polymer; and elevating the temperature of the polymer including the surface cross-linking agent at a speed of 3° C./min to 15° C./min, and carrying out a surface cross-linking reaction at 100° C. to 250° C.

Abstract: The invention relates to a method for the enzyme-catalysed hydrolysis of polyacrylic acid esters. According to said method, at least one polyacrylic acid ester is provided and incubated with at least one enzyme selected from enzymes (EC 3.1) acting on ester bindings, until the ester groups contained in the polyacrylic acid ester are partially or fully hydrolytically split, and optionally the modified polymer obtained thereby is isolated. The invention also relates to the enzymes used and mutants thereof, nucleic acids coding for the enzymes, vectors comprising the nucleic acids, micro-organisms comprising the vectors, and the use of the enzymes, the vectors or the micro-organisms for carrying out a method for the enzyme-catalysed hydrolysis of polyacrylic acid esters. The present application also relates to polymer reaction products that can be obtained by the method, and methods for producing esterases.

Abstract: The instant invention pertains to the preparation of polymers or copolymers wherein in a first step a controlled free radical polymerization process is carried out and in a second step the resulting polymer is modified by transesterification reactions. The final modified polymer or copolymer is useful as a dispersant for pigments. Further aspects of the invention are the thus prepared polymers or copolymers, a pigment concentrate containing the polymer or copolymer and a coating material containing the pigment concentrate.

Abstract: An adhesive composition and a polarizing plate, the adhesive composition including an isocyanate curing agent and having a creeping distance decrease rate of 10% or less, wherein the creeping distance decrease rate is calculated by Equation 1: Creeping distance decrease rate (%)=|(A?B)/A|×100, ??[Equation 1] wherein, in Equation 1, A and B are creeping distances of an adhesive layer prepared from the composition, when a force of 2.25 kg is applied to a polarizing plate at 25° C. for 1,000 seconds after the polarizing plate formed with the adhesive layer is attached to a glass plate and left at 35° C. and 45% RH for 24 hours and for 36 hours, respectively.

Abstract: The present invention relates to bone cements and, more particularly, to multi-solution bone cements and methods for making the same. An embodiment of the present invention provides multi-solution bone cements which include cross-linked PMMA beads, thereby providing for a significant increase in the polymer-to-monomer (P:M) ratio. Another embodiment of the present invention provides cross-linked PMMA beads which are surface modified with unsaturated carbon double bonds. A further embodiment of the present invention provides multi-solution bone cements made with PMMA-PMMA spherical brush polymers.

Abstract: A resin composition used to form a dye-receiving layer of a thermal transfer-receiving sheet in which the dye-receiving layer is formed on at least one surface of a substrate contains a core/shell-type latex including a core containing (A) and a shell containing (B) and a cross-linking agent that reacts with a carboxyl group contained in the shell. (A) is an acrylic resin at least containing, as one of its monomers, a substituted or unsubstituted phenoxyalkyl (meth)acrylate and/or a substituted or unsubstituted phenoxy polyalkylene glycol (meth)acrylate. (B) is a urethane resin containing a carboxyl group.

Abstract: Disclosed are ionomer compositions neutralized by a combination of cesium and potassium that have antistatic properties. Also disclosed are articles, including laminates and monolayer or multilayer structures comprising such compositions to which neither powders nor dusts easily adhere electrostatically.

Abstract: Disclosed is an optical planar thermoplastic resin composition including a lactone ring-containing polymer as a main component thereof, or including a lactone ring-containing polymer and at least one other thermoplastic resin. The optical planar thermoplastic resin composition of the present invention has high transparency, high heat resistance, and high optical isotropy, and therefore, can sufficiently exhibit characteristics according to various optical applications.

Abstract: The instant invention pertains to the preparation of polymers or copolymers wherein in a first step a controlled free radical polymerization process is carried out and in a second step the resulting polymer is modified by transesterification reactions. The final modified polymer or copolymer is useful as a dispersant for pigments. Further aspects of the invention are the thus prepared polymers or copolymers, a pigment concentrate containing the polymer or copolymer and a coating material containing the pigment concentrate.

Abstract: The present invention relates to bone cements and, more particularly, to acrylic-based orthopedic bone cements, their use in spinal applications, and methods for making the same. An embodiment of the present invention provides a method of grafting PMMA brushes on cross-linked PMMA nanospheres comprising at least one of the following steps: performing a hydrolysis reaction of surface methyl ester groups of said cross-linked PMMA nanospheres to form surface carboxylic acid groups of said cross-linked PMMA nanospheres; forming a 2-aminoethyl acrylate compound; coupling said surface carboxylic acid groups of said cross-linked PMMA nanospheres with said 2-aminoethyl acrylate compound to form a coupled compound with an initiating site; and grafting said PMMA brushes onto said initiating site.

Abstract: The present invention provides a sealing film for a solar cell having the improved heat resistance and light resistance and a solar cell made by using the same. A sealing film for a solar cell including ethylene/vinyl acetate copolymer and an organic peroxide, which includes a specific peroxycarbonate as the organic peroxide, and which includes a dihydroxydimethoxybenzophenone ultraviolet absorber without substantially including a hindered amine light stabilizer to prevent yellowing. A sealing film for a solar cell including ethylene/vinyl acetate copolymer and an organic peroxide, which includes a specific dialkylperoxide as the organic peroxide, and which includes dihydroxydimethoxybenzophenone ultraviolet absorber without substantially including monohydroxyalkoxybenzophenone ultraviolet absorber to prevent yellowing.

Abstract: The present invention provides a pressure-sensitive adhesive composition excellent in the anti-foaming release property and high-temperature stress relaxation property, and a pressure-sensitive adhesive layer composed of the pressure-sensitive adhesive composition. The invention relates to a pressure-sensitive adhesive composition including an acrylic polymer which is formed from a monomer component including methyl methacrylate and has a glass transition temperature (Tg) of ?40° C. or more, wherein the pressure-sensitive adhesive composition has a shear storage elastic modulus at 85° C. as measured by a dynamic viscoelasticity measurement of from 1×104 to 3×105 Pa.

Abstract: Provided is a modified ethylene-vinyl alcohol copolymer (C) having an ethylen content of 5 to 55 mol %, which contains a specific structural unit (I) in an amount of 0.3 to 40 mol % and may be obtained by reacting an ethylene-vinyl alcohol copolymer (A) with a monofunctional epoxy compound (B) having a molecular weight of not more than 500. This can be produced by a method for producing the modified ethylene-vinyl alcohol copolymer (C) which comprises melting and kneading an ethylene-vinyl alcohol copolymer (A) with a monofunctional epoxy compound (B) in an extruder. The modified ethylene-vinyl alcohol copolymer (C) is superior to a unmodified ethylene-vinyl alcohol copolymer (A) in transparency, stretchability, flexibility and flexing resistance due to the specific structural unit (I) incorporated therein, and thus, can be used as a barrier material in various applications requiring the above performance capabilities.

Abstract: The invention provides a process for preparing 1-alkoxy-2-methyl-1-oxopropan-2-yl(meth)acrylate, e.g. 1-methoxy-2-methyl-1-oxopropan-2-yl(meth)acrylate, by transesterifying alkyl ?-hydroxyisobutyrates. Copolymerization of such monomers in the preparation of poly(meth)acrylate-based moulding materials improves the heat distortion resistance thereof.

Abstract: A water-absorbing polymer structure is disclosed, whose surface has been brought into contact with a combination of a metal salt and an oxide of a metal. The invention also relates to a process for treating the surface of water-absorbing polymer structures whereby the surface of water-absorbing polymer structures is brought into contact with a combination of a metal salt and an oxide of a metal at a temperature of from about 50 to about 300° C. The present invention further relates to the water-absorbing polymer structures obtainable by this process, a composite comprising a water-absorbing polymer structure and a substrate, chemical products such as foams and fibers comprising water-absorbing polymer structures or a composite, and the use of a combination of an oxide of a metal and of a metal salt for treatment of the surface of super-absorbing polymer structures.

Abstract: A process for thermally surface postcrosslinking water-absorbing polymer particles in a fluidized bed generated by means of a carrier gas, wherein the surface postcrosslinker is supplied to the fluidized bed in gaseous form.

Abstract: The present invention relates to a moisture barrier for the protection of internal environment of sensitive devices comprising a homogeneous dispersion of superficially functionalized containing surface modifying organic group belonging to the same chemical class of at least one functional group of the polymeric compound, to a process for the production of said barrier and to sensitive device comprising such barriers.

Abstract: The copolymers include a hydrophobic monomer and an acryloyl or methacryloyl ester of a propylene glycol monomethyl ether, also referred to as 1-methyl-2-methoxyethyl acrylate (“MMOEA”). The combination of the hydrophobic monomer and the MMOEA monomer advantageously provides desired mechanical strength, biocompatibility, and drug permeability in the copolymers. The copolymers can advantageously be used on medical devices.

Abstract: The instant invention pertains to the preparation of polymers or copolymers wherein in a first step a controlled free radical polymerization process is carried out and in a second step the resulting polymer is modified by transesterification reactions. The final modified polymer or copolymer is useful as a dispersant for pigments. Further aspects of the invention are the thus prepared polymers or copolymers, a pigment concentrate containing the polymer or copolymer and a coating material containing the pigment concentrate.

Abstract: The present invention relates to resin syrup, which comprises a high-molecular-weight acrylic material containing a carboxyl group, and comprises a room-temperature-curing initiator and a high-temperature-curing initiator, and it also relates to an artificial marble containing a hardened form of the resin syrup, and to a production method for the same. The present invention can provide resin syrup having outstanding curing efficiency and a viscosity suitable for press molding by a process such as maturation because of the inclusion of the high-molecular-weight acrylic material containing a carboxyl group, the room-temperature-curing initiator, and the high-temperature-curing initiator, and it can provide an artificial marble containing a hardened form of the resin syrup, and a production method for the same.

Abstract: There is disclosed a polyvinyl alcohol having a 1,2-glycol bond in a side chain, and a process for preparing the polyvinyl alcolnol wherein there is no generation of dimethyl carbonate hence no need of a process of eliminating dimethyl carbonate in the recovering process of waste liquid after hydrolysis. Also, even when an introduction amount of 1,2-glycol bonds is increased, there is no deterioration of solubility in a hydrolyzing solution (methanol) of a copolymer (paste) before hydrolysis. Further, water-insolubility is not lowered even in experiencing thermal history. Specifically, there is provided a polyvinyl alcohol having a 1,2-glycol bond in a side chain obtained by hydrolyzing a copolymer of a vinyl ester monomer and a compound shown in the formula (1) wherein the hydrolysis degree of the polyvinyl alcohol is at least 60% by mol.

Abstract: The present invention relates to an acrylic pressure sensitive adhesive composition. More specifically, the present invention relates to an acrylic pressure sensitive adhesive composition which comprises a) acrylic copolymers; and b) a compound having an ester value of 200 or more. The acrylic pressure sensitive adhesive composition of the present invention has an excellent wettability to the surface of an adhered article with surface unevenness, an excellent endurance reliability, transparency, and stain resistance of adhered article, and a high-rate release property without any considerable change of adhesive properties.

Abstract: Low shear-thinning polyvinyl acetals having a solution viscosity in 30% strength by weight solution in methyl ethyl ketone which changes by not more than 10% in a shear rate range from 1 to 100 s?1. The preparation of the low shear-thinning polyvinyl acetals involves acetalation of partly hydrolyzed or completely hydrolyzed vinyl ester polymers comprising ?50 mol % of vinyl alcohol units with one or more aldehydes, optionally in the form of the hydrates, hemiacetals or full acetals, wherein from 0 to 60% by weight of the aldehyde, based on the total amount of the aldehyde, is initially introduced over the course of the first one to ten minutes of the acetalation and is prereacted over the course of from 1 to 30 minutes, and the remaining proportion is then metered in continuously over the course of at least 20 minutes.

Abstract: The present invention provides an ethylene-vinyl alcohol based copolymer (EVOH) having fundamentally improved thermal stability. The EVOH is characterized in that the proportion of ethylene units (III) is from 20 to 60 mole % with respect to the total (III+IV+V) of ethylene units (III), vinyl alcohol units (IV), and vinyl ester units (V), and the proportion of the total (I+II) of carboxylic acids units (I) and lactone ring units (II) in copolymer terminals with respect to the total (III+IV+V) is 0.12 mole % or less. The EVOH can be obtained by, for example, contacting a reducing agent with an ethylene-vinyl ester based copolymer before saponification and/or EVOH after saponification.

Abstract: Polyvinyl acetals with low solution viscosities and maximum Newtonian flow behavior contain sulphonate-functional vinyl ether or sulphonate-functional allyl ether units in addition to conventional vinyl ester, vinyl alcohol, and vinyl acetal units.

Abstract: A multi-layer nano-particle composition including a polymer core and at least two additional layers is provided. The nano-particles have a mean average diameter less than about 100 nm. The nano-particles can be modified via, for example, hydrogenation or functionalization. The nano-particles can be advantageously incorporated into rubbers, elastomers, and thermoplastics.

Abstract: Method for increasing the molecular weight of polyacrylates, in which polyacrylates, functionalized at least in part of their chain ends by functional groups X, are reacted with a compound having at least functional groups Y capable of linking reactions with functional groups X.

Abstract: Provided is a curable composition which can easily regulate the properties of a cured object prepared therefrom, which can prepare a cured object that does not substantially discolor or soften a finishing agent or coating material applied to the surface thereof, and which has a high curing rate in the inner regions. The curable composition contains (A) a polymer having at least one mercapto group at the molecular ends, the polymer being derived from a thiocarbonylthio group-containing polymer (a2) prepared by polymerizing a monomer (a1) which contains an acrylic ester as a principal component and which contains 50% by weight or more of the acrylic ester and less than 50% by weight of a monomer copolymerizable with the acrylic ester in the presence of a thiocarbonylthio group-containing compound; (B) a compound having at least two mercapto groups per molecule; and (C) an oxidizing agent.

Abstract: An antifouling coating which comprises a varnish comprised of a metal-containing acrylic resin having, in a side chain thereof, at least one group represented by the following formula (1): wherein X represents a group of the formula: n represents 0 or 1; Y represents a hydrocarbon group; M represents a metal; m represents an integer equal to [(the valence number of metal M)?1]; A represents an organic acid residue derived from a monobasic acid, said varnish having a nonvolatile fraction of not less than 40 weight % and a viscosity at 25° C. of not more than 18 poises and said antifouling coating having a volatile organic compound (VOC) content of not more than 400 g/L.

Abstract: A shaped medical device article prepared from a polymer melt composition comprising a polymer ester, a transesterification catalyst, and a tri- or tetraalkoxy silane, by forming and solidifying said composition, and after solidification, subjecting the composition to reaction conditions to effect hydrolysis at least some alkoxysilyl groups remaining in the composition to form silanol groups and to effect condensation of said silanol groups to form a ceramic network. The polymer ester may be a vinyl ester homopolymer or copolymer, or a polymer having ester groups in the backbone thereof.

Abstract: The invention relates to high-molecular, crosslinked polyvinyl butyrals, obtainable by (self-) crosslinking polyvinyl butyrals that contain coacetalated, acid-functionalized aldehydes. The invention also relates to a method for producing the same and to the use thereof.

Abstract: The present invention is concerned with a vinyl polymer having at least one group of the general formula (1) permolecule at the molecular chain terminus. —Z—R—CR1?CR2R3??(1) wherein Z represents an oxygen atom, a sulfur atom, a group of the formula NR?, R? represents a univalent hydrocarbon group containing 1 to 20 carbon atoms, or a bivalent organic group containing 1 to 20 carbon atoms, and R represents a carbonyl group, a direct bond or a bivalent organic group containing 1 to 20 carbon atoms; R1 and R2 are the same or different and each represents a hydrogen atom or a univalent organic group containing 1 to 20 carbon atoms, and R3 represents an organic group containing 1 to 20 carbon atoms. The present invention is further concerned with a curable composition comprising the above vinyl polymer.

Abstract: A method of inhibiting scale formation in a subterranean formation comprising: (a) injecting a suspension comprising particles of a controlled release scale inhibitor suspended in an aqueous medium into a formation through an injection well wherein the particles have a mean diameter of less than 10 microns, preferably less than 5 microns, more preferably less than 1 micron; (b) allowing the suspension to percolate through the subterranean formation towards a production well; and (c) controllably releasing the scale inhibitor from the particles in the near well bore region of the production well. Suitably, the particles of the controlled release scale inhibitor comprise an esterifiable scale inhibitor cross-linked with a polyol via ester cross-links.

Abstract: This invention provides a method for purification of a vinyl polymer which comprises the atom transfer radical polymerization of a vinyl monomer using a transition metal complex as the polymerization catalyst, said vinyl polymer being brought into contact with an oxidizing agent or a reducing agent.

Abstract: The present invention provides a method for producing hydroxyl group-containing polymer particles including causing cross-linked polymer particles containing a (meth)acrylate polymer to react in the presence of a metal-containing ester-exchange reaction catalyst with at least one compound selected from the group consisting of a compound including at least two hydroxyl groups and a compound including at least one primary amino group and at least one hydroxyl group, the cross-linked polymer particles comprising the (meth)acrylate polymer represented by the following formula (I): wherein R1 represents a hydrogen atom or a methyl group; R2 to R4 may be the same or different from each other, and each independently represents a substituted or non-substituted alkyl group or a substituted or non-substituted aryl group, any one of which has 1 to 12 carbon atoms; and n represents an integer of 1 or more.