JPH04275338A - Production of electron beam-crosslinkable paste resin and electron beam-crosslinkable plastisol using the same paste resin - Google Patents

Abstract

PURPOSE:To efficiently produce an electron beam-crosslinkable paste resin and obtain an electron beam-crosslinkable plastisol capable of providing good solvent resistance and heat resistance from the resultant paste resin. CONSTITUTION:An epoxy group-containing polyvinyl chloride or polymethyl methacrylate for particulate plastisol formation having 1X10<-5> to 1X10<-3>g equivalent epoxy group concentration of particle surface and 0.05-5mum average particle size is brought into contact with an unsaturated acid (e.g. chloroacrylic acid) of pka <4 to provide a particulate electron beam-curable paste resin having >=0.1 iodine value in polymerizable double bond amount of the particle surface. The above-mentioned paste resin is blended with a plasticizer (e.g. dimethyl phthalate) to provide an electron beam-crosslinkable plastisol.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for producing an electron beam crosslinkable paste resin and an electron beam crosslinkable plastisol using the paste resin. More specifically, the present invention provides a method for efficiently producing an electron beam crosslinkable paste resin suitable for use in electron beam crosslinkable plastisols, and a method for efficiently producing an electron beam crosslinkable paste resin containing the paste resin and a plasticizer as essential components. The present invention relates to an electron beam crosslinkable plastisol that can provide crosslinked molded products with excellent solvent resistance, heat resistance, etc. by electron beam irradiation.

0002

[Prior Art] Vinyl chloride paste resin can be handled as a liquid by dispersing it in a plasticizer to form a plastisol, and it can be solidified by heating, so it is a common thermoplastic. It can be applied to a much wider range of processing methods than that used for rubber or rubber, and is widely applied to, for example, flooring materials, wall covering materials, toys, automobile interior materials, and painted steel plates. Although plastisol is a thermoplastic resin, it can be processed like a thermosetting resin. This is due to the fact that the absorption rate of polyvinyl chloride changes rapidly across the glass transition temperature of the polyvinyl chloride. However, since plastisol is essentially a thermoplastic resin, it has the same problems as general polyvinyl chloride processed products, such as deformation and fusion at high temperatures. Was. By the way, it has been widely attempted to improve the heat deformation resistance of general polyvinyl chloride by crosslinking it with a chemical crosslinking agent. When conventional thermoplastic molding methods such as rolling and injection are used, crosslinking reactions occur simultaneously during processing and shaping processes, making it difficult to achieve both a sufficient degree of crosslinking and processability. On the other hand, with plastisol, which is liquid at room temperature when mixed and solidifies by heating and melting, by incorporating the chemical crosslinking agent into it, it is possible to prevent thermal deformation of molded products without impairing processability. It has the advantage of improving the wearer's appearance. However, the addition of a chemical crosslinking agent often results in a decrease in water resistance, weather resistance, transparency, etc., and for this reason, the current situation is that careful attention is required in processing and compounding. On the other hand, apart from such chemical crosslinking methods, a method of crosslinking using high-energy rays such as radiation is also known, but this method also causes decomposition of polyvinyl chloride, resulting in severe discoloration and is not practical. Recently, electron beam irradiation equipment with relatively low energy of about 150 to 300 KV has been put into practical use, and efforts are being made to make the equipment more compact and improve safety. No crosslinking was achieved. On the other hand, in addition to polyvinyl chloride, polymethyl methacrylate resin is known as a resin that can be processed into plastisol, but this resin also has the same problems as the polyvinyl chloride plastisol.

0003

Problems to be Solved by the Invention The present invention overcomes the drawbacks of conventional crosslinking methods, enables efficient crosslinking by low-energy electron beam irradiation, and provides an electron crosslinking method that can provide molded products with desirable physical properties. This was developed with the aim of providing a linearly crosslinkable plastisol.

0004

[Means for Solving the Problem] As a result of intensive research to develop an electron beam crosslinkable plastisol having the above-mentioned preferable properties, the present inventors have found that a specific particulate electron beam obtained by a specific production method has been developed. The inventors have discovered that the object can be achieved by using a plastisol containing a crosslinkable paste resin and a plasticizer, and have completed the present invention based on this knowledge.

That is, the present invention provides epoxy groups for processing particulate plastisol having an epoxy group concentration on the particle surface of 1 x 10-5 to 1 x 10-3 g equivalent/g and an average particle diameter of 0.05 to 5 μm. In a medium that does not dissolve the resin in the containing polyvinyl chloride or polymethyl methacrylate,
A method for producing a particulate electron beam crosslinkable paste resin having an iodine value of 0.1 or more and a polymerizable double bond content on the particle surface characterized by contacting with an unsaturated acid having a pKa of less than 4, and a method for producing a particulate electron beam crosslinkable paste resin, which is characterized by contacting with an unsaturated acid having a pKa of less than 4. The present invention provides an electron beam crosslinkable plastisol which contains a particulate electron beam crosslinkable paste resin and a plasticizer as essential components.

The present invention will be explained in detail below. The epoxy group concentration on the particle surface used in the present invention is 1×10
-5 to 1 x 10-3 g equivalent/g, and the average particle size is 0
．． Epoxy group-containing polyvinyl chloride or polymethyl methacrylate for processing particulate plastisol of 05 to 5 μm is
For example, (1) vinyl chloride or methyl methacrylate;
A method of copolymerizing an epoxy group-containing monomer copolymerizable with these and a copolymerizable monomer used as desired, (2) a normal particulate vinyl chloride paste mainly composed of vinyl chloride units; After dehydrochlorinating the resin in the presence of an alkali and forming double bonds in the polymer on the particle surface,
This can be produced by epoxidizing it with an epoxidizing agent such as peracetic acid.

Examples of the epoxy group-containing monomer copolymerizable with vinyl chloride or methyl methacrylate used in the method (1) include glycidyl ethers of unsaturated alcohols such as allyl glycidyl ether and methallyl glycidyl ether; Glycidyl methacrylate, glycidyl acrylate, glycidyl-p-vinylbenzoate, methylglycidyl itaconate, glycidyl ethyl maleate, glycidyl vinyl sulfonate,
Glycidyl esters of unsaturated acids such as glycidyl (meth)allylsulfonate, butadiene monoxide, vinylcyclohexene monoxide, 2-methyl-5,6
- Epoxide olefins such as epoxyhexene and the like can be mentioned. These epoxy group-containing monomers may be used alone or in combination of two or more.

Examples of monomers copolymerizable with vinyl chloride that can be used as desired include fatty acid vinyls such as vinyl acetate and vinyl propionate, ethylene, and propylene. Examples of monomers copolymerizable with methyl methacrylate include olefins such as olefins such as vinylidene chloride and vinylidene fluoride, vinyl ethers such as isobutyl vinyl ether, methyl vinyl ether, and cetyl vinyl ether. (meth) such as ethyl acrylate, butyl acrylate, butyl methacrylate, etc.
Examples include alkyl or alkanol esters of acrylic acid, acrylonitrile, styrene, ethylene, propylene, butadiene, isoprene, dimethyl maleate, dimethyl fumarate, and the like. Using these monomers,
There are no particular restrictions on the method for producing the epoxy group-containing paste resin, and methods conventionally used in the production of paste processing resins can be used, but seeded emulsion polymerization and fine suspension polymerization are particularly preferred. be.

The fine suspension polymerization method is a method in which an oil-soluble initiator is used as a catalyst, the particle size of monomer oil droplets is adjusted in advance by homogenization treatment before the start of polymerization, and homogeneous dispersion polymerization is carried out. In such a fine suspension polymerization method, an oil-soluble radical initiator is used as an initiator, and examples of the oil-soluble radical initiator include dibenzoyl peroxide, di-3,5,5-trimethylhexanoyl Peroxide, diacyl peroxides such as dilauroyl peroxide, diisopropyl peroxydicarbonate, di-sec-butylperoxydicarbonate, di-2-
peroxydicarbonates such as ethylhexylperoxydicarbonate, peroxyesters such as t-butylperoxypivalate and t-butylperoxyneodecanoate, or organic peroxides such as acetylcyclohexylsulfonyl peroxide and disuccinic acid peroxide; Examples include azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, and 2,2'-azobisdimethylvaleronitrile. These initiators may be used alone or in combination of two or more, and the amount used is appropriately selected depending on the type and amount of monomer, the preparation method, etc. body 1
The amount is selected in the range of 0.001 to 5.0 parts by weight per 00 parts by weight.

[0010] Furthermore, in the fine suspension polymerization method, a surfactant is usually used. Examples of the surfactant include alkyl sulfate salts such as sodium lauryl sulfate and sodium myristyl sulfate, alkylaryl sulfonates such as sodium dodecylbenzenesulfonate and potassium dodecylbenzenesulfonate, sodium dioctylsulfosuccinate, and dihexylsulfosuccinate. Sulfosuccinic acid ester salts such as sodium acid, fatty acid salts such as ammonium laurate and potassium stearate, anionic surfactants such as polyoxyethylene alkyl sulfate ester salts and polyoxyethylene alkylaryl sulfate ester salts, sorbitan monooleate, Sorbitan esters such as polyoxyethylene sorbitan monostearate, nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl esters, cetylpyridinium chloride, cetyltrimethylammonium Examples include cationic surfactants such as bromide,
These may be used alone or in combination of two or more, and the amount used is usually 0.05 to 5 parts by weight, preferably 0.2 to 5 parts by weight, per 100 parts by weight of the monomer used.
It is selected within the range of 4.0 parts by weight.

In this fine suspension polymerization method, first, the oil-soluble initiator, monomer, surfactant, and polymerization aids such as higher fatty acids and higher alcohols used as desired are added to an aqueous medium. and other additives, and premix by homogenizing with a homogenizer to adjust the particle size of oil droplets. Examples of the homogenizer include a colloid mill, a vibration stirrer, a two-stage high-pressure pump, a high-pressure jet from a nozzle or orifice, and ultrasonic stirring. Furthermore, the control of the particle size of oil droplets is influenced by the control of shear force during homogenization, stirring conditions during polymerization, type of reactor, amount of surfactants and additives, etc., but these are easily controlled. Appropriate conditions can be selected through preliminary experiments.

[0012] Next, the premix liquid homogenized in this manner is sent to a polymerization vessel, where the temperature is slowly raised while stirring, and polymerization is carried out at a temperature generally in the range of 30 to 80°C. In this way, the average particle diameter is 0.05 to 5.
A latex in which micron copolymer particles are homogeneously dispersed is obtained. This latex is usually subjected to known treatments such as salting out or spray drying, and the polymer is taken out as a solid. The molecular weight of the polymer is appropriately adjusted by adjusting the reaction temperature and molecular weight regulator depending on the purpose.

On the other hand, in the seeded emulsion polymerization method, resin particles prepared in advance by conventional emulsion polymerization or fine suspension polymerization are used as cores, and an anionic surfactant or an anionic surfactant and a nonionic surfactant are used in an aqueous medium. This is a method in which a polymerization reaction is carried out to enlarge the particles. The diameter of the core particles used in this case is usually in the range of 0.03 to 0.7 μm on average, and the amount used is usually 1 to 5 μm per 100 parts by weight of the monomer used.
It is selected within the range of 0 parts by weight.

Furthermore, as anionic surfactants,
Known substances usually used in emulsion polymerization, such as alkylbenzene sulfonates, alkyl sulfonates, alkyl sulfate salts, fatty acid metal salts, polyoxyalkyl ether sulfate salts, polyoxyethylene carboxylic acid ester sulfate salts, polyoxy Examples include ethylene alkyl phenyl ether sulfate salts and succinic acid dialkyl ester sulfonate salts, and these may be used alone or in combination of two or more.

Examples of nonionic surfactants include polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkyl ether glycerin borate, Compounds that have a polyoxyethylene chain in the molecule and have surface-active ability, such as polyoxyethylene alkyl ether phosphate and polyoxyethylene, and compounds in which the polyoxyethylene chain of the compound is a copolymer of oxyethylene and oxypropylene. Substituted compounds include sorbitan fatty acid ester, fatty acid glycerin ester, glycerin fatty acid ester, pentaerythritol fatty acid ester, etc., and these may be used alone or in combination of two or more. Regarding the amount of these surfactants used, anionic surfactants are usually selected in the range of 0.1 to 5 parts by weight per 100 parts by weight of monomers, and nonionic surfactants are usually selected in the range of 0.1 to 5 parts by weight. It is selected in a range of 0 to 5 parts by weight.

In this seeded emulsion polymerization, a combination of a water-soluble catalyst or a water-soluble reducing agent and an organic peroxide is used as an initiator. Examples of the water-soluble catalyst include potassium persulfate, ammonium persulfate, and hydrogen peroxide. The amount of these water-soluble catalysts used is 100% of the monomer used.
It is selected in the range of 0.001 to 5.0 parts by weight. The water-soluble reducing agent is, for example, a reducing agent that is soluble in water and used as a normal radical redox polymerization catalyst component, such as ethylenediaminetetraacetic acid or its sodium salt or potassium salt, or a combination thereof with iron, copper, chromium, etc. Complex compounds with heavy metals, sulfinic acid or its sodium salt or potassium salt, l-ascorbic acid or its sodium salt, potassium salt, calcium salt, ferrous pyrophosphate, ferrous sulfate, ferrous ammonium sulfate, sodium sulfite , acidic sodium sulfite, sodium formaldehyde sulfoxylate, reducing sugars, etc., and these may be used alone or in combination of two or more. The amount of these reducing agents used is 1
It is usually selected in the range of 0.00001 to 5 parts by weight per 00 parts by weight.

On the other hand, examples of organic peroxides include cumene hydroperoxide, p-cymene hydroperoxide, t-butylisopropylbenzene hydroperoxide, diisopropylbenzene hydroperoxide, p-
Examples include hydroperoxides such as menthane hydroperoxide, decalin hydroperoxide, t-amyl hydroperoxide, t-butyl hydroperoxide, and isopropyl hydroperoxide. These organic peroxides may be used alone or in combination of two or more, and the amount used is 10
The amount is selected in the range of 0.001 to 5 parts by weight per 0 parts by weight.

Next, a preferred example of the seeded emulsion polymerization method will be described. First, an aqueous emulsion of desired resin core particles is prepared, and then the water-soluble reducing agent and monomer are charged therein, followed by heating. and maintain the temperature at about 30-80°C. Separately, an aqueous emulsion of an organic peroxide and an aqueous surfactant solution are prepared using the surfactant, and these are mixed into an aqueous emulsion containing the resin core particles, a water-soluble reducing agent, and a monomer. It is continuously added to the emulsion while maintaining the temperature usually in the range of 30 to 80°C to carry out the polymerization reaction. In this seeded emulsion polymerization, higher fatty acids, higher alcohols, inorganic salts, water-soluble polymer compounds, etc. may be used in combination to enhance the effects of the surfactant and polymerization initiator used. After the polymerization reaction is completed, the copolymer is taken out as a solid from the emulsion containing the produced copolymer particles in the same manner as in the fine suspension polymerization method described above. The molecular weight of this copolymer is appropriately adjusted by adjusting the reaction temperature, molecular weight regulator, etc. depending on the purpose.

When producing an epoxy group-containing paste resin by these methods, the polymerization should be devised so that the epoxy group concentration on the particle surface is 1.0 x 10-5 to 1 x 10-3 g equivalent/g. It is important to do so. For example, it is preferable to introduce an epoxy group-containing monomer in the latter half of the polymerization reaction to increase the concentration of epoxy groups on the particle surface. Of course, it is possible to increase the surface epoxy group concentration of paste resin particles by copolymerizing a large amount of epoxy group-containing monomers, but many of the epoxy group-containing monomers are polyvinyl chloride and polymethyl methacrylate molecules. If a paste resin obtained by using a large amount of epoxy group-containing monomer is used to reduce the tension, a problem arises in that the viscosity tends to increase over time.

On the other hand, in the method (2) above, the alkali used for dehydrochlorination includes, for example, alkali metal or alkaline earth metal hydroxides such as sodium hydroxide, potassium hydroxide, and calcium hydroxide; Examples include inorganic alkalis such as alkali metal carbonates such as sodium carbonate and potassium carbonate, amines such as pyridine, dimethylaniline, and 1,8-diazabicyclo[5,4,0]undecene-7. In this method, a swelling agent can be used for the purpose of promoting dehydrochlorination and the subsequent epoxidation reaction, or adjusting the reaction depth from the particle surface. Examples of the swelling agent include aliphatic or aromatic hydrocarbons such as butane, hexane, and toluene, chlorinated hydrocarbons such as vinyl chloride, allyl chloride, and methylene dichloride, methanol, ethanol, propanol, ethylene glycol monopropyl ether, Examples include alcohols such as ethylene glycol diethyl ether and their ethers. Furthermore, organic solvents such as tetrahydrofuran, acetone, and methyl ethyl ketone, which are commonly known as solvents, can also be used as suitable swelling agents by mixing them with water and the above-mentioned swelling agents.

The dehydrochloric acid and subsequent epoxidation reactions are usually carried out in air or an inert gas, or in water or a medium that does not dissolve the vinyl chloride resin. Although this method has the advantage of increasing the concentration of epoxy groups on the particle surface, it has the disadvantage that the coloring caused by the dehydrochloric acid reaction is not completely decolored even by epoxidation. Therefore, in the present invention, the method (1) above is preferred as a method for producing an epoxy group-containing paste resin.

The epoxy group-containing paste resin must have a spherical particle shape necessary for a paste resin, and the average particle size must be in the range of 0.05 to 5 μm. This particle size distribution varies depending on the polymerization method, but
Those with a wide distribution with a peak of approximately 1 μm,
Such as those having both a relatively large narrow particle size distribution around 1 μm and a relatively small narrow particle size distribution of 0.3 μm or less, etc.
It is within the range of what is known as the particle size distribution of conventional paste resins. If this average particle diameter exceeds 5 μm, the efficiency of introducing electron beam crosslinkable double bonds will decrease, and
The density of the crosslinked molded article becomes low, and the object of the present invention cannot be achieved. Moreover, if the average particle diameter is smaller than 0.05 μm, the viscosity of the plastisol becomes high, and the viscosity increases over time, making it difficult to use.

The particle shape and particle size distribution of the epoxy group-containing paste resin can be determined by ultrasonically dispersing the paste resin in a medium such as water or alcohol, fixing it on a mesh covered with a collodion film, and observing it using an electron microscope. This can be confirmed by At this time, particle aggregates may be observed, but the particle diameter in the present invention refers to the diameter of a single particle excluding such particle aggregates. Moreover, the epoxy group concentration on the surface of the paste resin particles is 1.0×10 −5 to 1.0×10 −5 .
It is necessary that the amount is 0×10 −3 g equivalent/g. If the epoxy group concentration is less than 1.0 x 10-5 g equivalent/g, the desired electron beam crosslinkable paste resin cannot be obtained due to reaction with an unsaturated acid. Also 1.0×10-3
If the amount exceeds g equivalent/g, crosslinking between epoxy groups will be significant and gelation will be insufficient even when heated. The epoxy group concentration on the particle surface can be determined, for example, by adding the paste resin to a specified amount of methanol and dispersing it with ultrasonic waves.
It can be determined by adding a specified amount of hydrochloric acid to react with the epoxy group, and then titrating the unreacted excess hydrochloric acid with an alcoholic potassium hydroxide solution.

The epoxy group-containing paste resin having a predetermined surface epoxy group concentration obtained in this way can be used in a medium that does not dissolve it, and has an acid strength of less than 4.0 as expressed by pKa. By reacting with a strong unsaturated acid, the electron beam crosslinkable paste resin used in the present invention can be obtained. In the case of a weak acid with a pKa of 4.0 or more, the addition reaction with the epoxy group is difficult to proceed under mild conditions, so it is necessary to carry out the reaction at a higher temperature and for a longer time, or to use a tertiary amine or quaternary ammonium salt in combination. This results in the problem of discoloration of the reaction product.

Examples of the unsaturated acids having a pKa of less than 4.0 used in the present invention include halogen-substituted (meth)acrylic acids such as chloroacrylic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, and vinylsulfone. acids, unsaturated sulfonic acids such as ethyl (meth)acrylate-2-sulfonate, unsaturated sulfuric esters such as ethyl (meth)acrylate-2-sulfate, di-2-(meth)acryloxyethyl acid phosphate , di-2-(meth)acryloxypropyl acid phosphate, di-2
Examples include unsaturated acidic phosphoric acid esters such as -(meth)acryloxy-3-chloropropyl acid phosphate, and unsaturated dicarboxylic acids such as maleic acid and fumaric acid.

Examples of the medium that does not dissolve the paste resin used in the reaction between the unsaturated acid having a pKa of less than 4.0 and the epoxy group-containing paste resin include water, air, inert gas, dioctyl phthalate, trioctyl phosphate, and the like. Examples include plasticizers, alcohols, paraffins, halogenated paraffins, olefins, aromatic hydrocarbons, liquid amides, higher alkyl ketones, and those exemplified as swelling agents for paste resins. These may be used alone or in combination of two or more. Among these, those that can dissolve unsaturated acids and do not dissolve paste resin are preferred. Examples of such materials include methanol-vinyl chloride mixed systems, water-vinyl chloride systems, dimethylformamide-water systems, and plasticizers such as dioctyl phthalate and trioctyl phosphate.

[0027] If a medium capable of dissolving the epoxy group-containing paste resin is used as a medium, the resulting reactant will aggregate, making it impossible to prepare plastisol even when kneaded with a plasticizer. The reaction between the unsaturated acid and the epoxy group-containing paste resin is usually carried out at a temperature in the range of -10 to 95°C. It is preferable to do this at a lower temperature. In this reaction, accelerators such as tertiary amines and quaternary ammonium salts may be used if desired, and polymerization inhibitors such as hydroquinone, hydroquinone monomethyl ether, t-butylcatechol, and bisphenol A may be added. You can also do it.

If the reaction is carried out in a liquid medium, the electron beam crosslinkable paste resin after the reaction is dried to remove the medium and used as a dry powder. Of course, if a plasticizer is used as the medium, it can be used as it is to prepare plastisol. During the drying, as with normal paste resins, the drying temperature affects the degree of dispersion into the plasticizer, so it is desirable to select conditions that will not cause thermal fusion of the particles.

The electron beam crosslinkable paste resin according to the present invention thus obtained is a white powder having a surface iodine value of 0.1 or more and an average particle size of 0.05 to 5 μm. The surface iodine value is determined by dispersing 10 g of paste resin in chloroform and measuring it according to JIS K-8004. This surface iodine value is 0.
When it is less than 1, crosslinking by electron beam is insufficient.

The electron beam crosslinkable plastisol of the present invention contains the electron beam crosslinkable paste resin obtained as described above and a plasticizer as essential components. There are no particular restrictions on the plasticizer, and those conventionally used as plastisol plasticizers, such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, di-(
2-ethylhexyl) phthalate, di-n-octyl phthalate, diisobutyl phthalate, diheptyl phthalate, diphenyl phthalate, diisodecyl phthalate, ditridecyl phthalate, diundecyl phthalate,
Phthalic acid derivatives such as di(heptyl, nonyl, undecyl) phthalate, benzyl phthalate, butylbenzyl phthalate, dinonyl phthalate, dicyclohexyl phthalate, dimethyl isophthalate, di-(2-ethylhexyl) isophthalate, diisooctyl isophthalate, etc. Isophthalic acid derivatives, tetrahydrophthalic acid derivatives such as di-(2-ethylhexyl)tetrahydrophthalate, di-n-octyltetrahydrophthalate, diisodecyltetrahydrophthalate, di-n-butyl adipate, di-(2-ethylhexyl)adipate, diisodecyl adipate , adipic acid derivatives such as diisononyl adipate, azelaic acid derivatives such as di-(2-ethylhexyl) azelate, diisooctyl azelate, di-n-hexyl azelate, di-n-butyl sebacate, di-(2-ethylhexyl) Sebacic acid derivatives such as sebacate, maleic acid derivatives such as di-n-butyl maleate, dimethyl maleate, diethyl maleate, di-(2-ethylhexyl) maleate, di-n-
Fumaric acid derivatives such as butyl fumarate, di-(2-ethylhexyl) fumarate, tri-(2-ethylhexyl) trimellitate, tri-n-octyl trimellitate, triisodecyl trimellitate, triisooctyl trimellitate, tri-n-hexyl trimellitate,
Trimellitic acid derivatives such as triisononyl trimellitate, pyromellitic acid derivatives such as tetra-(2-ethylhexyl)pyromellitate, tetra-n-octylpyromellitate, triethyl citrate, tri-n-butyl citrate, acetyl Citric acid derivatives such as triethyl citrate, acetyl tri-(2-ethylhexyl) citrate, monomethyl itaconate, monobutyl itaconate, dimethyl itaconate, diethyl itaconate, dibutyl itaconate, di-(2-ethylhexyl) itaconate, etc. Itaconic acid derivatives, oleic acid derivatives such as butyl oleate, glyceryl monooleate, diethylene glycol monooleate, ricinoleic acid derivatives such as methyl acetyl ricinoleate, butylacetyl ricinoleate, glyceryl monoricinoleate, diethylene glycol monoricinoleate, n-butyl stearate , stearic acid derivatives such as glycerin monostearate, diethylene glycol distearate, diethylene glycol monolaurate, diethylene glycol dipelargonate, other fatty acid derivatives such as pentaerythritol fatty acid ester, triethyl phosphate, tributyl phosphate, tri-(2-ethylhexyl) phosphate, tributoxyethyl phosphate,
Phosphoric acid derivatives such as triphenyl phosphate, cresyl diphenyl phosphate, tricresyl phosphate, tricylenyl phosphate, tris(chloroethyl) phosphate, diethylene glycol dibenzoate, dipropylene glycol dibenzoate, triethylene glycol dibenzoate, triethylene glycol dibenzoate -(2-ethylbutyrate), triethylene glycol di-(2-ethylhexoate), glycol derivatives such as dibutylmethylene bisthioglycolate, glycerol monoacetate, glycerol triacetate,
glycerin derivatives such as glycerol tributyrate,
Epoxy derivatives such as epoxidized soybean oil, epoxybutyl stearate, di-2-ethylhexyl epoxyhexahydrophthalate, diisodecyl epoxyhexahydrophthalate, epoxytriglyceride, epoxidized octyl oleate, epoxidized decyl oleate, adipic acid type Examples include polyester plasticizers such as polyester, sebacic acid polyester, and phthalic acid polyester, partially hydrogenated terphenyl, adhesive plasticizers, and polymerizable plasticizers such as diallyl phthalate, acrylic monomers, and oligomers. . These plasticizers may be used alone or in combination of two or more. Further, the use of a polymerizable plasticizer can be said to be a preferable method from the viewpoint of causing co-crosslinking with the paste resin, but if the amount of this polymerizable plasticizer used is large, the molded product obtained tends to be hard and brittle.

The plastisol of the present invention may contain other additive components conventionally used in plastisols, such as stabilizers, thickeners, diluents, ultraviolet absorbers, and light stabilizers, to the extent that the object of the present invention is not impaired. , pigments, dyes, fillers, adhesion promoters, reinforcing agents, etc. The plastisol of the present invention can be formed into a desired shape by conventional plastisol processing methods such as coating, extrusion, dipping, casting, slush, rotation, and spraying, and then irradiated with electron beams. By this method, a crosslinked molded article can be obtained.

[0032] As the electron beam used for crosslinking, an electron beam using an electron beam accelerator is preferable from the viewpoint of absorption dose control, safety, and ease of introduction into the manufacturing process. For crosslinking with an electron beam, it is preferable to use an electron beam accelerator with an electron beam accelerating voltage of 100 to 750 KV, preferably 150 to 300 KV, and apply the irradiation so that the absorbed dose is about 0.5 to 20 megarads.

[0033]

EXAMPLES Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to these examples in any way.

Production Example 1 Production of epoxy group-containing vinyl chloride paste resin Sodium hydrogen carbonate 10g, water 20kg, dioctyl sulfosuccinate 50g, dioctyl phthalate 200g
After putting 40 g of dioctyl peroxydicarbonate into a pressure-resistant container equipped with a stirrer and deaerating it, 7 kg of vinyl chloride was added and mixed with stirring for 30 minutes. The reaction solution was transferred to a reaction vessel via a homogenizer, and the temperature of the reaction solution was raised to 42° C. to initiate polymerization. When the polymerization conversion rate reached 60%, a homogeneous mixture of 1250 g of vinyl chloride and 250 g of glycidyl methacrylate was continuously injected into the reactor at a rate of 300 g/hour. Total polymerization conversion rate after injection is 75%
Met. When the polymerization was further advanced and the conversion rate reached 85%, 50 g of a 20% by weight methanol solution of bisphenol A was injected as a polymerization inhibitor to stop the polymerization reaction, and then cooled (polymerization solution A). After removing unreacted vinyl chloride from a portion of polymerization solution A by heating and reducing pressure, it was dried with a spray dryer and pulverized to obtain an epoxy group-containing vinyl chloride resin (resin A1). The average particle size of this material is 0.
92 μm, and the surface epoxy group concentration was 3.2×10 −5 g equivalent/g.

The surface epoxy group concentration was measured as follows. That is, 5 g of resin, 1 ml of 1N hydrochloric acid aqueous solution, and 100 ml of methanol were placed in a 300 ml wide-mouthed glass container with a stopper, mixed for 1 hour using a magnetic stirrer, and then subjected to ultrasonic treatment at 40°C.
Titrate with an alcoholic solution of KOH in N (titer volume aml
). On the other hand, the titration amount (6 ml) of a blank was measured in the same manner without adding the resin, and the surface epoxy concentration was determined using the following formula. Surface epoxy concentration (g equivalent/g) = [f1-(b-
a) f2 x 0.1]/w x 10-3 f1: Factor f2 of 1N HCl solution: Factor w of 1/10N KOH solution: Weight g of sample

Production Example 2 Production of epoxy group-containing vinyl chloride paste resin After charging 900 ml of water, 100 g of seed latex (PVC homopolymer latex, solid content 35% by weight), and 3 g of potassium persulfate into a 3-liter autoclave, it was degassed. , the temperature was raised to 50°C. 700g of vinyl chloride under stirring
After press-fitting, add sodium lauryl sulfate aqueous solution (5g
/200ml) at a rate of 1ml/min, and further added glycidyl methacrylate aqueous solution (7g/200ml) at a rate of 1ml/min.
50 ml) was continuously added under stirring at a rate of 0.4 ml/min for copolymerization. The copolymerization reaction was completed in 6 hours, and the conversion rate was 88%. Next, this copolymer latex was spray dried to obtain an epoxy group-containing vinyl chloride resin (resin A2). This one is 0.95μm and 0
．． The average particle size was 0.8 μm with a particle size distribution having a distribution peak at 20 μm, and the surface epoxy group concentration was 3×10 −6 g equivalent/g.

Production Example 3 Production of epoxy group-containing polymethyl methacrylate paste resin Same as Production Example 1 except that methyl methacrylate was used instead of vinyl chloride and 20 g of dodecyl mercaptan was added as a chain transfer agent. and epoxy group-containing polymethyl methacrylate (resin B
1) was manufactured. The final polymerization conversion rate was 97%, and resin B1
The average particle size is 1.2 μm, and the surface epoxy group concentration is 2.0
x10-5 g equivalent/g.

Electron beam crosslinkable paste resin Example 1 100 parts by weight of resin A1 was mixed and dispersed in 300 parts by weight of methanol and further dispersed at 40°C for 40 minutes using an ultrasonic dispersion machine, followed by 2-acrylamide-2-methyl. It was charged into an autoclave with 5 parts by weight of propane sulfonic acid (pKa=2.0), and after stirring and degassing, 5 parts by weight of vinyl chloride
0 parts by weight were injected. After continuing mixing and contact at 40°C for 1 hour, vinyl chloride was recovered, the methanol layer was removed by sedimentation separation method, 400 parts by weight of methanol was newly added, and the washing operation by stirring and mixing-sedimentation separation was repeated 5 times. The precipitate was filtered and deliquified and dried at room temperature to obtain Resin C. This resin C has an average particle size of 0.97 μm and a surface iodine value of 0.
．． 6 white powder.

Example 2 In Example 1, maleic acid (pKa=1.
Resin D was obtained in the same manner as in Example 1, except that 94) was used and the mixing contact temperature was 80°C. Resin D was a white powder with a particle size of 1.01 μm and a surface iodine value of 0.5.

Example 3 A mixture of 5 parts by weight of di-2-methacryloxyethyl acid phosphate (pKa=2.3) and 20 parts by weight of vinyl chloride was added to 300 parts by weight of polymerization solution A, and mixed and contacted at 40°C for 1 hour. After this, the vinyl chloride was recovered, and the polymer solution dispersion was dried and ground using a spray dryer to obtain Resin E. Resin E was a white powder with an average particle size of 0.92 μm and a surface iodine value of 7.0. In addition, after washing resin E with methanol, the surface iodine value was measured and found to be 1.2.

Example 4 Example 3 except that 3 parts by weight of maleic acid was used instead of 5 parts by weight of 2-methacryloxyethyl acid phosphate, and the mixing contact temperature was changed to 80°C.
Resin F was obtained in the same manner as above. Resin F has an average particle size of 0
．． It was a white powder with a diameter of 94 μm and a surface iodine value of 6.5.

Example 5 Resin G was obtained in the same manner as in Example 1 except that resin B1 was used instead of resin A1. Resin G was a white powder with an average particle size of 1.2 μm and a surface iodine value of 0.4.

Comparative Example 1 In Example 1, Zeon 121 [
Resin H was obtained in the same manner as in Example 1, except that 100 parts by weight of vinyl chloride homopolymer paste resin (manufactured by Nippon Zeon Co., Ltd.) was used. Resin H has an average particle size of 1.2μ
m, the surface iodine value was less than 0.1.

Comparative Example 2 In Example 1, Zeon 121 was used instead of resin A1, and 1,8-diazabicyclo[5,4,0]undecene-7 was used instead of 2-acrylamido-2-methylpropanesulfonic acid. Resin I was obtained in the same manner as in Example 1, except that , and vinyl chloride was not used. Resin I was a reddish brown powder with an average particle size of 1.2 μm and a surface iodine value of 9.2.

Comparative Example 3 Resin J was obtained in the same manner as in Example 2 except that 2-aminoethyl methacrylate was used instead of maleic acid. Resin J has an average particle size of 0.97 μm
It was a yellow powder with a surface iodine value of 0.9.

Comparative Example 4 Resin K was obtained in the same manner as in Example 1 except that resin A2 was used instead of resin A1. Resin K was a white powder with an average particle size on the large particle side of 0.95 μm, an average particle size on the small particle side of 0.22 μm, and a surface iodine value of less than 0.1.

Electron beam crosslinkable plastisol Example 6, Comparative Example 5 100 parts by weight of the paste resin shown in Table 1, 55 parts by weight of dioctyl phthalate, 20 parts by weight of titanium oxide toner, and 3 parts by weight of dibasic lead sulfite. Plastisol was prepared by mixing in a mortar. Next, after degassing this plastisol, it was applied onto a steel plate treated with an acrylic epoxy primer to a thickness of 300 μm.
While heating at ℃ for 2 minutes, satin embossing was performed using a roll (convex part 0.2R, distance between vertices 1.2 mm), and then processed using an electrocurtain type electron beam accelerator (manufactured by Energy Science). Piezo voltage 168KV, irradiation amount 10
An electron beam was irradiated under Mrad's conditions to obtain a resin-coated steel plate.

[0048] This resin-coated steel plate was evaluated as follows. The results are shown in Table 1. (1) Yellowness was measured using a color computer manufactured by Hue Suga Test Instruments. (2) Cut a solvent-resistant steel plate into 20 mm squares, and
0 ml and shaken for 24 hours, and the presence or absence of dissolution of the coating film was observed. (3) An embossed heat-resistant steel plate was cut out to a size of 20 x 100 mm, and the degree of retention of the emboss on the surface when heated at 220° C. for 1 minute was visually observed and evaluated according to the following criteria. ○: No change, △: Emboss blur, ×: Disappearance

0049
]

[Table 1]

Note 1) C/G weight ratio = 70/30

0
Example 7, Comparative Example 6 100 parts by weight of paste resin of the type shown in Table 2, 55 parts by weight of dioctyl phthalate, 20 parts by weight of heavy calcium carbonate
Plastisol was prepared by mixing 15 parts by weight of titanium oxide, 6 parts by weight of azodicarbonamide, 3 parts by weight of Na-Zn stabilizer, 8 parts by weight of mineral spirit, and 0.5 parts by weight of sodium dodecylbenzenesulfonate. . Next, the plastisol was coated on flame retardant paper to a thickness of 170 μm, heated at 150°C for 1.5 minutes to gel, and the coating thickness was measured.
It was heated and foamed in an oven at 0°C. After measuring the foaming ratio m1 of the obtained resin foam, an acceleration voltage of 162
The foam was irradiated with an electron beam under the conditions of KV and irradiation dose of 5 Mrad, then reheated for 1 minute at a surface temperature of 220°C using a far-infrared oven, and the magnification m2 of the foam was measured, and the magnification retention rate m
2/m1 was calculated. These results are shown in Table 2.

[0052]

[Table 2]

Note 1) The foam was crushed and the thickness could not be measured accurately.

[0054]

According to the present invention, an electron beam crosslinkable paste resin suitable for use in electron beam crosslinkable plastisol can be efficiently produced. Further, the electron beam crosslinkable plastisol of the present invention can be irradiated with a low energy electron beam to give a crosslinked molded article having favorable properties such as excellent solvent resistance and heat resistance.

Claims (2)

[Claims] Claim 1: The epoxy group concentration on the particle surface is 1×10-5
~1 x 10-3 g equivalent/g, and the average particle size is 0.0
Polymerizable dihydrogen on the particle surface is characterized by contacting epoxy group-containing polyvinyl chloride or polymethyl methacrylate for processing particulate plastisol of 5 to 5 μm with an unsaturated acid having a pKa of less than 4 in a medium that does not dissolve the resin. A method for producing a particulate electron beam crosslinkable paste resin having a heavy bond content and an iodine value of 0.1 or more. 2. An electron beam crosslinkable plastisol comprising a particulate electron beam crosslinkable paste resin obtained by the production method according to claim 1 and a plasticizer as essential components.