JP2000159844A - Vinyl chloride graft copolymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vinyl chloride graft copolymer which maintains mechanical strengths such as tensile strength, flexural modulus, etc., of a vinyl chloride resin and imparts well a transparency and an impact resistance. SOLUTION: A vinyl chloride graft copolymer is prepared by graft copolymerizing, against from 3 to 25 wt.% acrylic copolymer comprising from 51 to 100 pts.wt. (meth)acrylate monomer component of which a homopolymer has a glass transition temperature of at least -140 deg.C but below 30 deg.C, from 49 to 0 pts.wt. radically polymerizable monomer component which is copolymerizable with this and from 0.1 to 30 pts.wt. polyfunctional monomer component, from 7 to 40 wt.% radically polymerizable monomer of which a homopolymer has a refractive index of from 1.32 to 1.47 and from 90 to 35 wt.% vinyl chloride.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vinyl chloride graft copolymer, and more particularly to a vinyl chloride graft copolymer having excellent transparency and impact resistance.

[0002]

2. Description of the Related Art Vinyl chloride resins have been used in a wide range of applications because they are transparent and have excellent mechanical strength, weather resistance and chemical resistance. However, so-called "hard" products that do not contain an external plasticizer are limited in use because of low impact resistance and the like. In order to improve the impact resistance of these hard vinyl chloride resin products, various improvement proposals have been made since ancient times.

As a method for improving the impact resistance of a vinyl chloride resin, for example, Japanese Patent Application Laid-Open No. 60-25813 discloses a vinyl chloride resin obtained by graft copolymerizing vinyl chloride with an acrylic copolymer. I have. However, the above-mentioned vinyl chloride-based resin is used because the impact resistance is improved as the amount of added rubber component is increased, but on the other hand, the mechanical strength such as tensile strength and flexural modulus tends to decrease. The use is greatly restricted.

Japanese Patent Application Laid-Open No. Hei 8-225622 discloses that
There is disclosed a vinyl chloride resin obtained by graft copolymerizing vinyl chloride with an acrylic copolymer having a core-shell structure. However, the above-mentioned vinyl chloride resin does not significantly reduce the mechanical strength such as the tensile strength and the flexural modulus together with the impact resistance, but is inferior in transparency and is used in applications where transparency is required. It could not be expanded.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above facts, and has as its object to maintain the mechanical strength of a vinyl chloride resin, such as tensile strength and flexural modulus, An object of the present invention is to provide a vinyl chloride-based graft copolymer capable of imparting good transparency and impact resistance.

[0006]

The vinyl chloride graft copolymer according to the first aspect of the present invention has a (meth) acrylate monomer component having a glass transition temperature of -140 to less than 30 ° C. 100 parts by weight, 3 to 25% by weight of an acrylic copolymer composed of 49 to 0 parts by weight of a radical polymerizable monomer component copolymerizable therewith and 0.1 to 30 parts by weight of a polyfunctional monomer component, and It is characterized in that a radical polymerizable monomer having a refractive index of 1.32 to 1.47 and vinyl chloride are graft-copolymerized at a ratio of 7 to 40% by weight and 90 to 35% by weight, respectively.

The vinyl chloride graft copolymer according to the second aspect of the present invention is the vinyl chloride graft copolymer according to the first aspect, wherein the homopolymer has a glass transition temperature of -14.
51 to 100 parts by weight of a (meth) acrylate-based monomer component having a temperature of 0 to less than 30 ° C, 49 to 0 parts by weight of a radical polymerizable monomer component copolymerizable therewith, and 0.1 to 30 parts by weight of a polyfunctional monomer component The homopolymer has a refractive index of 1.3 to 3 to 25% by weight of an acrylic copolymer composed of
It is obtained by graft copolymerizing a radical polymerizable monomer of 5 to 1.42 and vinyl chloride at a ratio of 10 to 25% by weight and 87 to 50% by weight, respectively.

The homopolymer used in the present invention has a glass transition temperature (Tg) of from -140 to less than 30 ° C. (meth).
Although the acrylate monomer is not particularly limited, for example, ethyl acrylate (Tg = −24 ° C.,
Hereinafter, only the temperature is shown in parentheses), n-propyl acrylate (-37 ° C), isopropyl acrylate (-6
° C), n-butyl acrylate (-54 ° C), isobutyl acrylate (-24 ° C), sec-butyl acrylate (-21 ° C), n-butyl methacrylate (20 ° C).
C), n-hexyl acrylate (-57C), cyclohexyl acrylate (15C), n-hexyl methacrylate (-5C), 2-ethylhexyl acrylate (-85C), n-octyl acrylate (-85C).
C), n-octyl methacrylate (-25C), isooctyl acrylate (-45C), n-nonyl acrylate (-63C), n-nonyl methacrylate (-3C).
5 ° C.), isononyl acrylate (−85 ° C.), n-decyl acrylate (−70 ° C.), n-decyl methacrylate (−45 ° C.), lauryl methacrylate (−65 ° C.)
C), 2-hydroxyethyl acrylate (-15
C), 2-hydroxypropyl acrylate (-7
° C).

The Tg value of a homopolymer of a (meth) acrylate monomer is described in “Polymer Data Handbook (Basic)”, edited by The Society of Polymer Science, Japan (1986), published by Baifukan.
It depends on. When the Tg of the homopolymer of the (meth) acrylate monomer is less than -140, the mechanical strength such as tensile strength and flexural modulus of the product molded from the obtained vinyl chloride graft copolymer is sufficiently high. If the temperature is 30 ° C. or higher, sufficient flexibility and impact resistance may not be obtained.

The radical polymerizable monomer copolymerized with the (meth) acrylate-based monomer is used as a comonomer for the purpose of improving weather resistance, chemical resistance, and reducing tackiness during molding. Not necessary. These radical polymerizable monomers are not particularly limited, but include, for example, methyl methacrylate (Tg = 105 ° C., hereinafter, only the temperature is shown in parentheses),
Ethyl methacrylate (65 ° C), n-propyl methacrylate (35 ° C), isopropyl methacrylate (8
1 ° C), isobutyl methacrylate (53 ° C), sec
-Butyl methacrylate (107 ° C.), t-butyl acrylate (37 ° C.), t-butyl methacrylate (10
7 ° C.), alkyl (meth) acrylates such as cyclohexyl methacrylate (83 ° C.), palmityl methacrylate and stearyl acrylate; 2-hydroxyethyl methacrylate (55 ° C.), 2-hydroxypropyl methacrylate (75 ° C.), 2-acryloyloxy Polar group-containing vinyl monomers such as ethyl phthalic acid; aromatic vinyl monomers such as styrene, α-methylstyrene, p-methylstyrene, and p-chlorostyrene; unsaturated nitriles such as acrylonitrile and methacrylonitrile; vinyl acetate and propion And vinyl esters such as acid vinyl. These radical polymerizable monomers may be used alone, or two or more kinds may be used in combination.

When the amount of the radical polymerizable monomer exceeds 49 parts by weight, the flexibility of the obtained vinyl chloride graft copolymer is impaired, and the impact resistance is lowered. preferable.

The polyfunctional monomer copolymerized with the (meth) acrylate monomer crosslinks the acrylic copolymer and prevents the vinyl chloride graft copolymer particles from being destroyed during the molding process. In addition to improving the impact resistance of the copolymer molded article, it also makes it difficult for vinyl chloride-based graft copolymer particles to coalesce before and after the molding process, and reduces the adhesiveness of the vinyl chloride-based graft copolymer particles. Used as a comonomer for purposes.

Although these polyfunctional monomers are not particularly limited, for example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate
Acrylate, 1,6-hexanediol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethylene oxide-modified trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) (Meth) acrylates such as acrylate, dipentaerythritol hexa (meth) acrylate,
Allyl compounds such as diallyl phthalate, diallyl maleate, diallyl fumarate, diallyl succinate, triallyl isocyanurate, divinyl compounds such as divinylbenzene, and dienes such as butadiene are exemplified. These polyfunctional monomers may be used alone,
More than one species may be used in combination.

If the amount of the polyfunctional monomer is less than 0.1 part by weight, the impact resistance of a product molded from the obtained vinyl chloride graft copolymer cannot be sufficiently improved. On the other hand, if it is more than 30 parts by weight, it becomes a hard and brittle molded product, the impact resistance is reduced, and the flexibility is remarkably reduced. Therefore, it is limited to 0.1 to 30 parts by weight, preferably 0.1 to 30 parts by weight. 15 parts by weight.

The method for obtaining the acrylic copolymer is not particularly limited, and examples thereof include an emulsion polymerization method, a suspension polymerization method, and a dispersion polymerization method. Among them, the emulsion polymerization method is a preferred polymerization method because the particle size of the obtained acrylic copolymer is easily controlled. The emulsion polymerization method is not particularly limited, and a known method such as a batch polymerization method, a monomer addition method, and an emulsion dropping method can be appropriately selected and used. In the above polymerization, an emulsifying dispersant, a polymerization initiator, a pH adjuster, an antioxidant and the like are used as necessary.

Examples of the emulsifying dispersant include anionic surfactants, nonionic surfactants, partially saponified polyvinyl alcohol, cellulose dispersants, and gelatin. Among them, anionic surfactants are preferably used, and examples thereof include polyoxyethylene nonyl phenyl ether sulfate.

Examples of the polymerization initiator include water-soluble polymerization initiators such as ammonium persulfate, potassium persulfate, and hydrogen peroxide; organic peroxide-based polymerization initiators such as benzoyl peroxide and lauroyl peroxide; An azo compound-based polymerization initiator such as butyronitrile is exemplified.

When the acrylic copolymer is prepared by an emulsion polymerization method, the solid content of the obtained acrylic copolymer latex is preferably 10 to 60% by weight in view of productivity, stability of polymerization reaction and the like. is there. Further, a protective colloid agent may be added to the obtained acrylic copolymer latex as needed after the completion of the polymerization reaction, for the purpose of improving the mechanical stability of the latex.

If the average particle size of the obtained acrylic copolymer is too large, both the impact resistance and the tensile strength are reduced. If the average particle size is too small, the impact resistance is reduced.
Preferably it is about 0.01 to 0.3 μm.

The obtained acrylic copolymer is graft-copolymerized with a radical polymerizable monomer having a homopolymer refractive index of 1.32 to 1.47 and vinyl chloride. If the ratio of the acrylic copolymer in the polymer is too low, sufficient impact resistance cannot be obtained, and if it is too high, the mechanical strength such as bending strength and tensile strength is reduced. % By weight.

The refractive index of the homopolymer of the radical polymerizable monomer graft-copolymerized on the acrylic copolymer is as follows:
It is from 1.32 to 1.47, preferably from 1.35 to 1.42. If the refractive index of the homopolymer of the radical polymerizable monomer is less than 1.32, the resulting vinyl chloride-based graft copolymer molded article cannot have high transparency, and 1.47.
Is exceeded, similarly high transparency cannot be obtained, so that it is limited to the above range. Further, a vinyl chloride-based graft copolymer molded article in which only a vinyl chloride monomer is graft-polymerized on an acrylic copolymer also has a milky white color, and high transparency cannot be obtained.

With respect to the transparency of the obtained vinyl chloride graft copolymer molded article, the reason that the radical polymerizable monomer has an appropriate range in the refractive index of the homopolymer is that the refractive index of the acrylic copolymer is high. Rate is 1.46 ~
Since the refractive index of polyvinyl chloride is about 1.51 to 1.55 while the refractive index is about 1.50, the refractive index of the homopolymer of the radical polymerizable monomer as the graft comonomer is limited to the above range. This is presumed to be because the refractive index of the graft portion of the vinyl chloride / radical polymerizable monomer can be made as close as possible to the refractive index of the acrylic copolymer.

The homopolymer has a refractive index of 1.32 to 1.47.
The radical polymerizable monomer of is not particularly limited, for example, vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, ethylene fluoride derivatives such as trifluorochloroethylene, vinyl acetate, vinyl trifluoroacetate , Vinyl esters such as vinyl propionate and vinyl pentafluoropropionate, vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether, isobutyl vinyl ether, pentyl vinyl ether, hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether and dodecyl vinyl ether, ethyl acrylate, Trifluoroethyl (meth) acrylate, 2-heptafluorobutoxyethyl acrylate, 2- (1,1,2,2-
Tetrafluoroethoxy) -ethyl acrylate, 2-
Trifluoroethoxy-ethyl acrylate, 2,2
2-trifluoro-1-methylethyl methacrylate,
3-ethoxypropyl acrylate, trifluoroisopropyl methacrylate, pentafluoropropyl acrylate, tetrafluoro-3- (trifluoromethoxy) -propyl acrylate, tetrafluoro-3-
(Pentafluoroethoxy) -propyl acrylate,
Tetrafluoro-3- (heptafluoropropoxy)-
Propyl acrylate, butyl acrylate, t-butyl methacrylate, heptafluorobutyl acrylate, 2,2,3,4,4,4-hexafluorobutyl acrylate, octafluoropentyl acrylate, nonafluoropentyl acrylate, undecafluorohexyl acrylate, penta (Meth) acrylates such as decafluorooctyl acrylate.
In addition, the refractive index of the homopolymer of the above-mentioned radical polymerizable monomer was based on "Polymer Handbook" by Willie Interscience.

The ratio of the radical polymerizable monomer having a refractive index of 1.32 to 1.47 of the homopolymer graft-copolymerized with vinyl chloride is 3 to 25% by weight of the acrylic copolymer. -40% by weight, vinyl chloride ratio 90-35% by weight. When the orientation ratio of the radical polymerizable monomer is less than 7% by weight, transparency is reduced,
If it exceeds 40% by weight, impact resistance and flexibility may be reduced, and it may be difficult to obtain a vinyl chloride-based graft copolymer having desired transparency, impact resistance and flexibility. Furthermore, in order to impart transparency, impact resistance and flexibility in a well-balanced manner, the homopolymer has a refractive index of 1.35 to 1.35.
It is preferable that the orientation ratio of the radical polymerizable monomer of 1.42 is 10 to 25% by weight and the mixing ratio of vinyl chloride is 87 to 50% by weight based on 3 to 25% by weight of the acrylic copolymer.

The means for graft-copolymerizing the above-mentioned acrylic copolymer with a radical polymerizable monomer having a homopolymer having a refractive index of 1.32 to 1.47 together with vinyl chloride is not particularly limited. For example, a suspension polymerization method, an emulsion polymerization method, a solution polymerization method, a bulk polymerization method and the like can be mentioned. Among them, the suspension polymerization method is suitably used because of high productivity of the vinyl chloride graft copolymer. In the suspension polymerization method, a dispersant and an oil-soluble polymerization initiator are used, and a coagulant may be added as needed for the purpose of preventing the scale from adhering to the polymerization tank.

In the suspension polymerization method, a dispersant is added for the purpose of improving the dispersion stability of the acrylic copolymer latex and efficiently performing the graft copolymerization. The dispersant is not particularly limited, but includes, for example, poly (meth) acrylate, (meth) acrylate-alkyl acrylate copolymer, methyl cellulose, ethyl cellulose, hydroxypropyl methyl cellulose, polyethylene glycol, Polyvinyl acetate and its partially saponified product, gelatin, polyvinylpyrrolidone, starch,
And maleic anhydride-styrene copolymer. These may be used alone or in combination of two or more.

The above-mentioned oil-soluble polymerization initiator is not particularly restricted but includes, for example, lauroyl peroxide,
t-butyl peroxypivalate, diisopropyl peroxy dicarbonate, dioctyl peroxy dicarbonate, t-butyl peroxy neodecanoate, α-
Oil-soluble polymerization initiators such as organic peroxides such as cumyl peroxy neodecanoate, and azo compounds such as 2,2-azobisisobutyronitrile and 2,2-azobis-2,4-dimethylvaleronitrile. Is mentioned. These may be used alone or in combination of two or more.

In the suspension polymerization method, the acrylic copolymer is charged into a polymerization reactor in the form of an emulsion before starting the polymerization. The radical polymerizable monomer having a refractive index of 1.32 to 1.47 may be charged in its entirety before the start of the polymerization, and the dripping thereof is started together with the start of the polymerization, and then added continuously or intermittently. It may be added dropwise in a continuous manner. In particular, when the monomer reactivity ratio is significantly different from that of vinyl chloride, which is a graft comonomer, it is possible to add either of the above-mentioned radical polymerizable monomer or vinyl chloride monomer in a divided manner to obtain a transparent vinyl chloride-based graft copolymer. It is preferable in that the property is further improved. In the suspension polymerization method, a pH adjuster, an antioxidant and the like may be added as necessary.

When a radical polymerizable monomer and vinyl chloride are graft-copolymerized to the acrylic copolymer by a suspension polymerization method, for example, pure water, an oil-soluble polymerization initiator, After adding a copolymer latex, a dispersant, an oil-soluble polymerization initiator, a water-soluble thickener, and a radical polymerizable monomer having a refractive index of 1.32 to 1.47, the inside of the reactor is sealed, and the inside of the reactor is sealed. After removing the air, the vinyl chloride monomer and other vinyl monomers as needed are added while stirring the inside of the reactor, and the inside of the reactor is heated to a predetermined temperature to start graft copolymerization. The reaction is terminated while adjusting the inside of the reactor to a predetermined temperature by the heat medium in the jacket. After the completion of the reaction, unreacted vinyl chloride monomer and other vinyl monomers are removed to obtain a slurry-like vinyl chloride graft copolymer. This is dehydrated and dried to obtain a vinyl chloride graft copolymer product.

The degree of polymerization of the obtained vinyl chloride-based graft copolymer is not particularly limited, but if the degree of polymerization is too small, the impact resistance of the obtained molded article decreases,
If it is too large, the moldability will be reduced and the resulting molded article will be hard and brittle, so it is preferably from 300 to 2,000, more preferably from 400 to 1600.

The above vinyl chloride graft copolymer is used alone as a molding material, but may also be used as a modifier for a vinyl chloride resin. When the vinyl chloride-based graft copolymer is used as a molding material, the vinyl chloride-based graft copolymer may contain, as necessary, a heat stabilizer, a stabilizing aid, a lubricant, a processing aid, and an antioxidant. , A light stabilizer, a filler, a coloring agent, a plasticizer, and the like are added, and these additives can be added in the same manner as a commonly used vinyl chloride resin.

Examples of the heat stabilizer include dimethyltin mercapto, dibutyltin mercapto, dioctyltin mercapto, dibutyltin maleate, dibutyltin maleate polymer, dioctyltin malate, dioctyltin maleate polymer, dibutyltin laurate, and dibutyltin laurate. Organic tin-based stabilizers such as rate polymers, calcium-zinc-based stabilizers, barium-zinc-based stabilizers, and the like.

Examples of the stabilizing aid include epoxidized soybean oil, epoxidized linseed oil, epoxidized tetrahydrophthalate, epoxidized polybutadiene, phosphate esters and the like. Examples of the lubricant include montanic acid wax, paraffin wax, polyethylene wax, stearic acid, stearyl alcohol, butyl stearate and the like.

Examples of the processing aid include a processing aid composed of an alkyl acrylate / alkyl methacrylate copolymer having a weight average molecular weight of 100,000 to 2,000,000.
Specific examples include, for example, an n-butyl acrylate / methyl methacrylate copolymer and a 2-ethylhexyl acrylate / methyl methacrylate / butyl methacrylate copolymer. Examples of the antioxidant include a phenolic antioxidant. Examples of the light stabilizer include a salicylic acid ester-based, benzophenone-based, benzotyriazole-based, cyanoacrylate-based ultraviolet absorber, and a hindered amine-based light stabilizer.

Examples of the filler include calcium carbonate, talc and the like. As a coloring agent, for example,
Organic pigments such as azo, phthalocyanine, sulene and dye lakes; and inorganic pigments such as metal oxides, molybdenum chromate, sulfides / selenides, ferrocyanides, and the like. Further, a plasticizer may be added for the purpose of improving workability at the time of molding, and examples of these plasticizers include dibutyl phthalate and di-2-ethylhexyl adipate.

The above-mentioned vinyl chloride-based graft copolymer can be used in combination with a commonly used vinyl chloride-based resin such as an extrusion molding method, an injection molding method, a blow molding method, a vacuum molding method, a calendar molding method, a press molding method and the like. It can be molded similarly.

The technique relating to the vinyl chloride-based graft copolymer of the present invention can also be applied to a post-chlorinated vinyl-based graft copolymer. For example, 95-30 parts by weight of a (meth) acrylate monomer component having a homopolymer having a glass transition temperature of −140 to less than 30 ° C. and a refractive index of the homopolymer of 1.56 to 1.75. A refractive index of 1.54 parts by weight of a radical polymerizable monomer component copolymerizable therewith and 0.1 to 30 parts by weight of a polyfunctional monomer component is 1.54.
Graft copolymerization of vinyl chloride alone or vinyl chloride as a main component, and a vinyl monomer copolymerizable therewith at a ratio of 99 to 70% by weight with respect to 1 to 30% by weight of an acrylic copolymer of 1.57 to 1.57. The resulting vinyl chloride graft copolymer is a post-chlorinated vinyl graft copolymer obtained by post-chlorination so that the chlorine content increases by 0.5 to 15% by weight.

The homopolymer has a Tg of -140 to 30 ° C.
As the (meth) acrylate-based monomer that is less than the same, the (meth) acrylate-based monomer used in the invention of claim 1 is similarly used.

When the content ratio of the (meth) acrylate-based monomer component is less than 30 parts by weight, a product molded from the obtained vinyl chloride-based graft copolymer is imparted with appropriate flexibility and impact resistance. When the content exceeds 95 parts by weight, it is difficult to impart impact resistance at low temperatures, so that the content is limited to the above-mentioned parts by weight. The preferred content by weight of the (meth) acrylate-based monomer component is 80 to
95 parts by weight.

The homopolymer has a refractive index of 1.56-1.
The radical polymerizable monomer copolymerizable with the (meth) acrylate monomer of 75 is intended to improve weather resistance and chemical resistance, to reduce tackiness at the time of molding, etc. It is used as a comonomer for the purpose of adjusting the refractive index, and the polyfunctional monomer component 0.1 to 95 to 30 parts by weight of the (meth) acrylate monomer component.
Along with 1 to 30 parts by weight, 5 to 70 parts by weight are contained as components in the acrylic copolymer having a refractive index of 1.54 to 1.57.

The refractive index of the homopolymer is 1.56-1.
Examples of the radical polymerizable monomer copolymerizable with the 75 (meth) acrylate-based monomer include, but not particularly limited to, polar group-containing alkyl (meth) acrylates such as chlorobenzyl methacrylate, phenyl methacrylate, and benzyl methacrylate. Such as aromatic alkyl (meth) acrylate, methacrylic acid, 2-acryloyloxyethyl phthalic acid, vinyl monomer having a polar group such as vinylidene chloride, styrene, α-methylstyrene, o, m, p-methylstyrene, o, m , P-propylstyrene, o, m, p-chlorostyrene, etc., and the like, and these may be used alone or in combination of two or more. In addition, the refractive index of the radical polymerizable monomer was based on "Polymer Handbook" of Willie Interscience. However, the refractive index of poly (2-ethylhexyl acrylate) is 1.
At 463, the refractive index of trimethylolpropane triacrylate was 1.48.

If the amount of the radical polymerizable monomer added to the (meth) acrylate-based monomer is too large, sufficient impact resistance of the vinyl chloride-based graft copolymer cannot be obtained. Acrylic copolymer having not obtained, too little, not only does not improve the transparency of the vinyl chloride-based graft copolymer no matter how the combination of monomers is changed, the acrylic having a desired refractive index Since a copolymer cannot be obtained, the content ratio is limited to the above.

The polyfunctional monomer copolymerized with the radical polymerizable monomer crosslinks the acrylic copolymer as described in the first aspect of the present invention and obtains a vinyl chloride graft copolymer. These polyfunctional monomers are added not only for improving the impact resistance but also for the purpose of preventing coalescence of the acrylic copolymer latex particles at the time of production and after production. And the polyfunctional monomers used in the invention of the present invention, and these can be used alone or in combination of two or more.

If the addition amount of the polyfunctional monomer is less than 0.1 part by weight, the particles of the acrylic copolymer cannot maintain an independent particle shape in the vinyl chloride-based graft copolymer resin. Impact properties are reduced. If the amount exceeds 30 parts by weight, the impact resistance of the obtained vinyl chloride-based graft copolymer resin becomes difficult to obtain due to excessive crosslinking density, so that it is limited to the above range.

Means for obtaining an acrylic copolymer having a refractive index of 1.54 to 1.57 from the above (meth) acrylate-based monomer, radical-polymerizable monomer and polyfunctional monomer is not particularly limited. For example, claim 1
The polymerization means used in the described invention can be used similarly.

As described above, the content (parts by weight) of each component of the (meth) acrylate monomer, the radical polymerizable monomer and the polyfunctional monomer depends on the refractive index of the obtained acrylic copolymer. 1.54 to approximately the same as the refractive index (1.55 to 1.58) of the vinyl-based graft copolymer
It is determined to be in the range of 1.57 and copolymerized.
When the refractive index is less than 1.54 or more than 1.57, irregular reflection of light occurs at the interface between the acrylic copolymer and the vinyl chloride graft copolymer component, and the transparency of the post-chlorinated vinyl chloride copolymer is obtained. Sex is impaired.

The refractive index of the acrylic copolymer can be approximately estimated from the following formula based on the refractive index of the homopolymer of each monomer constituting the acrylic copolymer and the weight fraction of each monomer in the acrylic copolymer. The weight fraction of each monomer is determined from the refractive index of the post-chlorinated vinyl chloride graft copolymer and the known refractive index of each monomer used.

[0048]

(Equation 1)

In the present invention, means for obtaining the acrylic copolymer is not particularly limited, and examples thereof include an emulsion polymerization method and a suspension polymerization method. Further, the emulsion polymerization method is preferable because the particle size of the latex can be easily controlled. In the emulsion polymerization method, an emulsifying dispersant, a polymerization initiator, and the like are used, and a pH adjuster, an antioxidant, and the like may be added as necessary.

The emulsifying dispersant is added for the purpose of improving the dispersion stability of the emulsion polymerization monomer composition in the emulsion and efficiently conducting the polymerization. Examples of the emulsifying dispersant include anionic surfactants and nonionic surfactants. Agents, partially saponified polyvinyl acetate, cellulosic dispersants, gelatin and the like. Above all, anionic surfactants are preferably used. Examples of the anionic surfactant include, but are not particularly limited to, polyoxyethylene nonylphenyl ether sulfate and the like.

Examples of the polymerization initiator include water-soluble polymerization initiators such as potassium persulfate, ammonium persulfate and aqueous hydrogen peroxide, organic peroxides such as benzoyl peroxide and lauroyl peroxide, and azobisisobutyro. An azo initiator such as nitrile is exemplified.

The above-mentioned emulsion polymerization methods are roughly classified into three methods, namely, a batch polymerization method, a monomer dropping method, and an emulsion dropping method, depending on the difference in the monomer addition method, but are not particularly limited, and any of these methods is used. be able to. The batch polymerization method is, for example, a method in which pure water, an emulsifying dispersant, the above-mentioned acrylic monomer, a radical polymerizable monomer copolymerizable therewith, and an emulsion polymerization monomer composition comprising a polyfunctional monomer are collectively placed in a jacketed polymerization reactor. In this method, the mixture is emulsified sufficiently by stirring under conditions of oxygen removal by a nitrogen stream and pressurization, the inside of the vessel is heated to a predetermined temperature by a jacket, and then a polymerization initiator is added to carry out polymerization. With the monomer dropping method, for example, pure water, an emulsifying dispersant, and a polymerization initiator are put in a polymerization reactor with a jacket, and under a condition of oxygen removal and pressurization under a nitrogen stream, the inside of the vessel is first set to a predetermined volume by a jacket. After the temperature is raised, the emulsion polymerization monomer composition is added dropwise in a predetermined amount, thereby gradually polymerizing.

The emulsion dripping method means, for example, that the emulsified monomer is prepared in advance by sufficiently emulsifying the above-mentioned emulsion-polymerized monomer composition, emulsifying dispersant and pure water by stirring, and then adding the emulsified monomer into a jacketed polymerization reactor. A method in which water and a polymerization initiator are added, and under conditions of oxygen removal and pressurization under a nitrogen stream, the inside of the vessel is first heated to a predetermined temperature by a jacket, and then the above-mentioned emulsified monomer is dropped by a predetermined amount to carry out polymerization. is there. Further, in the emulsion dropping method, if a method is used in which a part of the above-mentioned emulsified monomer is added all at once in the early stage of polymerization (hereinafter referred to as a seed monomer) and then the remaining emulsified monomer is dropped, the amount of the seed monomer can be changed. The particle size of the produced latex can be easily controlled.

The resin solid content of the acrylic copolymer latex obtained after the polymerization reaction is not particularly limited, but is preferably 10 to 60% by weight in view of the productivity of the latex and the stability of the polymerization reaction. preferable.

The average resin particle diameter of the acrylic copolymer latex is preferably not more than 0.3 μm because the transparency of the vinyl chloride resin decreases as the average resin particle diameter increases.
The particle size is not particularly limited as long as it is not more than μm.
μm or more is appropriate. More preferably, 0.01 to 0.2.
3 μm.

The above acrylic copolymer latex includes:
For the purpose of improving the mechanical stability of the latex emulsion, a protective colloid agent may be added as needed after the completion of the latex polymerization reaction.

If the proportion of the copolymer latex containing the acrylic polymer in the vinyl chloride resin is small, it is difficult to obtain sufficient impact resistance, and if the proportion is large, the mechanical strength such as bending strength and tensile strength is low. Because the strength is low,
It is 1 to 30% by weight, preferably 4 to 20% by weight.

In the method for obtaining a vinyl chloride-based graft copolymer by graft-copolymerizing vinyl chloride alone or vinyl chloride as a main component and a vinyl monomer copolymerizable therewith with the acrylic copolymer latex, The term “mainly composed of vinyl” means that vinyl chloride is contained in an amount of 50% by weight or more, and the copolymerizable monomer is a generally known vinyl monomer and is not particularly limited. Examples include vinyl acetate, alkyl (meth) acrylate, alkyl vinyl ether, ethylene, vinyl fluoride, and maleimide, and at least one of them can be used.

The method of graft-copolymerizing vinyl chloride alone or vinyl chloride as a main component with the acrylic copolymer latex and copolymerizing a vinyl monomer copolymerizable therewith is not particularly limited. Examples thereof include a suspension polymerization method, an emulsion polymerization method, a solution polymerization method, and a bulk polymerization method. Among them, the suspension polymerization method is suitably used. The suspension polymerization is performed in the same manner as the method used in the first aspect of the present invention.

Examples of the method for post-chlorination of the obtained vinyl chloride graft copolymer include a thermal chlorination method and a photo chlorination method, and the photo chlorination method is preferred from the viewpoint of coalescence. . As a chlorinating system, any of a gas phase chlorination method, a solution chlorination method, and a suspension chlorination method may be used.
The increase in the chlorine content of the vinyl chloride-based graft copolymer accompanying the post-chlorination is 0.5 to 15% by weight.
If it is less than 0.5% by weight, the transparency and the heat deformation resistance decrease,
If the content exceeds 15% by weight, the impact resistance decreases, so that the content is limited to the above range.

The vinyl chloride graft copolymer obtained by the production method of the present invention may be used, if necessary, at the time of molding, as a heat stabilizer, a stabilizing aid, a lubricant, a processing aid, an antioxidant, a light stabilizer. Agents, fillers, pigments and the like are added. These additives are
Although none of them is particularly limited, for example, the additives listed in the first aspect of the present invention are the same.

The vinyl chloride graft copolymer according to the first aspect of the present invention comprises the above-mentioned (meth) acrylate monomer, a radical polymerizable monomer copolymerizable therewith, and a polyfunctional monomer in the above-mentioned ratio. The refractive index of the vinyl chloride matrix that constitutes the graft portion is determined by graft copolymerization of the vinyl chloride monomer and the radical polymerizable monomer having a refractive index of the homopolymer of 1.32 to 1.47 in the above ratio. Polymerization controls the refractive index of the vinyl chloride matrix, reduces irregular reflection of light at the interface between the acrylic copolymer and the vinyl chloride matrix, and increases transparency while maintaining high impact resistance. It can be held according to the altitude.

The vinyl chloride graft copolymer according to the second aspect of the present invention is the same as the acrylic copolymer according to the first aspect, except that the refractive index of the vinyl chloride matrix constituting the graft portion is changed to the vinyl chloride monomer. By graft copolymerizing a radical polymerizable monomer having a homopolymer having a refractive index of 1.35 to 1.42 at the above ratio, the refractive index of the vinyl chloride matrix is more reliably controlled, and the acrylic copolymer portion and It can reduce the irregular reflection of light at the interface of the vinyl chloride matrix portion, and can maintain a high degree of transparency while maintaining high impact resistance.

The post-chlorinated vinyl chloride-based graft copolymer described above has a homopolymer having a refractive index of 1.56 to 1.5 as a comonomer of the above (meth) acrylate-based monomer.
By containing the components of the radical polymerizable monomer and the polyfunctional monomer copolymerizable with the 1.75 (meth) acrylate monomer in the above-described ratio, the refractive index of the acrylic copolymer can be increased. Graft polymerization of a vinyl chloride monomer to the coalesced product, and further, a chlorine content of 0.5 to 1
By controlling the refractive index in the range substantially equal to the refractive index of the post-chlorinated vinyl chloride matrix so as to increase by 5% by weight, irregular reflection of light at the interface between the acrylic copolymer portion and the vinyl chloride matrix portion is reduced. In addition, it is possible to maintain a high degree of transparency while maintaining high impact resistance and heat deformation resistance.

[0065]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

(Examples 1 to 6, Comparative Examples 1 to 6) According to the composition shown in Table 1, each vinyl chloride resin was obtained by the following operation procedure.

(Preparation of Copolymer Latex Containing Acrylic Polymer) First, a predetermined amount of pure water, an emulsifying dispersant (polyoxyethylene nonylphenyl ether ammonium sulfate), and 2-ethylhexyl acrylate (hereinafter abbreviated as 2-EHA). ), N-butyl acrylate (hereinafter abbreviated as n-BA), and trimethylolpropane triacrylate (hereinafter abbreviated as TMPTA) were mixed and stirred to prepare an emulsified monomer.

On the other hand, pure water was charged into a reaction vessel equipped with a stirrer and a reflux condenser, and oxygen in the vessel was replaced with nitrogen. Then, the temperature of the reaction vessel was raised to 70 ° C. under stirring conditions. In the reactor where the temperature was raised, ammonium persulfate (hereinafter, APS) was added.
) And 30% by weight of the above emulsified monomer were collectively charged as a seed monomer to initiate polymerization. Subsequently, the remainder of the emulsified monomer was dropped into the reactor. After the dropping of all emulsified monomers was completed in 3 hours, and after an aging period of 1 hour, the polymerization was terminated by cooling, and an acrylic polymer latex having a solid concentration of about 30% by weight (hereinafter simply referred to as latex) was used. ).

(Preparation of vinyl chloride graft copolymer)
Then, 3% of pure water, the latex, and partially saponified polyvinyl acetate were placed in a reaction vessel equipped with a stirrer and a jacket.
Aqueous solution, t-butyl peroxy neodecanoate, α-
Cumyl peroxy neodecanoate was charged all at once, then the air in the polymerization vessel was exhausted with a vacuum pump, and vinyl chloride was further charged under stirring conditions, and then polymerization was performed at a polymerization temperature of 57 ° C by controlling the jacket temperature. Started. For Comparative Example 1, the above procedure was followed, and for Examples 1 and 2, and Comparative Examples 2 and 4-6, the vinyl chloride monomer was divided into 40 portions in 5 hours immediately after the polymerization was started. In Examples 4 to 6 and Comparative Example 3, the graft copolymerization was performed by pressing the radical polymerizable monomers shown in Table 1 into the reaction vessel in 40 times in 5 hours. After completion of the press-fitting of the grafting monomer into the reaction vessel, the mixture is aged for 10 minutes,
After that, the reaction was stopped by cooling. After completion of the reaction, unreacted vinyl chloride monomer was removed, and further dehydration drying was performed to obtain a vinyl chloride-based graft copolymer having a polymerization degree of vinyl chloride of about 1000 in the vinyl chloride-based graft copolymer.

In order to evaluate the performance of the vinyl chloride graft copolymers obtained in Examples 1 to 6 and Comparative Examples 1 to 6, the degree of polymerization was measured according to a conventional method, and the impact resistance, light transmittance and haze were measured. The value was evaluated by the method shown below. The evaluation results are shown in Table 1.

[Impact Resistance] A Charpy impact test was performed according to JIS K 7111. The sample was roll-kneaded at 200 ° C. for 3 minutes with a resin composition in which 0.5 parts by weight of an organotin stabilizer and 1.0 part by weight of a montanic acid lubricant were mixed with 100 parts by weight of a vinyl chloride-based graft copolymer. After doing
It was prepared from a 3 mm-thick press plate obtained by press molding at 200 ° C. for 3 minutes. The measurement temperature is 23 ° C.

[Light Transmittance] The light transmittance was measured in accordance with JIS K 7105. [Haze] Haze was measured according to JIS K 7105.

[0073]

[Table 1]

(Reference Examples 1 to 7, Comparative Examples 7 to 10) According to the composition shown in Table 2, each vinyl chloride resin was obtained by the following operation procedure.

(Preparation of Copolymer Latex Containing Acrylic Polymer) A (meth) acrylate shown in Table 2 and a radical polymerizable monomer copolymerizable therewith, trimethylolpropane triacrylate, were emulsified in the same manner as in Example 1. A monomer was prepared. Meanwhile, pure water was charged into a reaction vessel equipped with a stirrer and a reflux condenser, and oxygen in the vessel was replaced with nitrogen. Then, the temperature of the reaction vessel was raised to 70 ° C. under stirring conditions. APS and a predetermined amount of the emulsified monomer were collectively charged as a seed monomer into the reactor where the temperature was raised, and polymerization was started. Subsequently, the remainder of the emulsified monomer was dropped into the reactor. The dropping of all the emulsified monomers was completed in 3 hours, and after an aging period of 1 hour, polymerization was terminated by cooling, and an acrylic polymer latex having a solid concentration of about 30% by weight was obtained.

(Preparation of vinyl chloride graft copolymer)
Then, 3% of pure water, the latex, and partially saponified polyvinyl acetate were placed in a reaction vessel equipped with a stirrer and a jacket.
Aqueous solution, t-butyl peroxy neodecanoate, α-
Cumyl peroxy neodecanoate was charged all at once, then the air in the polymerization vessel was discharged with a vacuum pump, and vinyl chloride monomer was further charged under stirring conditions. The polymerization was started. The completion of the reaction was confirmed when the pressure in the reactor was reduced to a pressure of 7 kg / cm ² , and the reactor was stopped. Thereafter, the unreacted vinyl chloride monomer was removed, and the polymer was further dehydrated and dried to obtain a vinyl chloride-based graft copolymer having a degree of polymerization of vinyl chloride of about 1000 in the vinyl chloride-based graft copolymer.

(Post-chlorination) Next, the vinyl chloride graft copolymer was charged in its entirety into a pressurized reaction vessel (volume: 5 liters) provided with a glass lining equipped with a stirrer, and ion-exchanged water was further added. Introduce chlorine gas from the phase,
The chlorination reaction is carried out at a chlorine gas pressure in the reaction vessel at normal pressure, a reaction temperature of 70 ° C. and an ultraviolet light intensity of 20 W until the chlorine amount increases by a predetermined weight%, and a post-chlorinated vinyl chloride graft copolymer is produced. Obtained.

In order to evaluate the performance of the chlorinated vinyl chloride-based graft copolymers obtained in Reference Examples 1 to 7 and Comparative Examples 7 to 10, the degree of polymerization was measured according to a conventional method, and the impact resistance and the Vicat softening were measured. The temperature, light transmittance and haze value were evaluated by the following methods. Table 2 shows the evaluation results.

[Impact Resistance] A Charpy impact test was conducted in accordance with JIS K 7111. A sample was prepared by mixing a resin composition obtained by mixing 0.5 parts by weight of an organic tin-based stabilizer and 1.0 part by weight of a montanic acid-based lubricant with respect to 100 parts by weight of a vinyl chloride-based resin, and then kneading the roll at 200 ° C. for 3 minutes. It was produced from a 3 mm-thick press plate obtained by press molding at 200 ° C. for 3 minutes. The measurement temperature is 23 ° C.

[Vicat Softening Temperature] Using the above pressed plate, a Vicat softening temperature test was performed according to JIS K7206. [Light Transmittance] The light transmittance was measured according to JIS K 7105.

[Haze] Haze was measured according to JIS K 7105.

[0082]

[Table 2]

[0083]

Since the vinyl chloride graft copolymer of the present invention is constituted as described above, the vinyl chloride resin maintains mechanical strength such as tensile strength and flexural modulus and has excellent transparency. Properties and impact resistance can be obtained in a well-balanced manner. Therefore, the molded article obtained by using this can be used for a wide range of uses such as building materials, roofing materials, soundproof walls, lighting signs, and siding materials that make use of transparency.

Further, as can be seen from the Reference Examples, after applying the technique relating to the vinyl chloride-based graft copolymer of the present invention, the chlorinated vinyl chloride-based graft copolymer becomes excellent in transparency and impact resistance. Thus, since high heat deformation resistance is imparted, it is possible to provide a molded article for a wide range of uses together with the flame retardancy of the post-chlorinated vinyl chloride-based graft copolymer.

Claims (2)

[Claims] The glass transition temperature of the homopolymer is -140.
(Meth) acrylate-based monomer component having a temperature of -30 ° C or less, 51 to 100 parts by weight, a copolymerizable radical polymerizable monomer component 49 to 0 parts by weight, and a polyfunctional monomer component 0.1 to 30 parts by weight. Acrylic copolymer 3
The refractive index of the homopolymer is 1.32 to 25% by weight.
1.47 The radical polymerizable monomer and vinyl chloride are
A vinyl chloride-based graft copolymer obtained by graft copolymerization at a ratio of 7 to 40% by weight and 90 to 35% by weight, respectively. 2. The glass transition temperature of the homopolymer is -140.
(Meth) acrylate-based monomer component having a temperature of -30 ° C or lower, 51-100 parts by weight, a radical polymerizable monomer component copolymerizable therewith, 49-0 parts by weight, and a polyfunctional monomer component 0.1-30 parts by weight. The homopolymer has a refractive index of 1.35 based on 3 to 25% by weight of an acrylic copolymer composed of
2. The vinyl chloride graft copolymer according to claim 1, wherein the radical polymerizable monomer and vinyl chloride are graft copolymerized at a ratio of 10 to 25% by weight and 87 to 50% by weight, respectively.