JPH06220272A - Styrene-based plastisol composition - Google Patents

Abstract

PURPOSE:To obtain the subject compsn. which does not generate a halogen compd. even when burned and hence does not cause pollution, has a low viscosity, is excellent in stability in long storage at room temp., and gives a sheet hardly exhibiting plasticizer bleeding. CONSTITUTION:This plastisol compsn. comprises an ionically crosslinked resin powder and a plasticizer. This resin powder is obtd. by the microsuspension polymn. of a monomer mixture comprising 50-85 pts.wt. styrenic monomer, 10-45 pts.wt. monomer radical-copolymerizable with styrene, and 0.2-10 pts.wt. radical-polymerizable unsatd. carboxylic acid, and ionically crosslinking the resulting copolymer having a mean primary particle size of 0. 5-3mum with a mono- or divalent metal cation.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is a novel polystyrene plastisol composition, and more specifically, it suppresses generation of harmful acidic gas when a plastic molded product is disposed of, and has a low viscosity and enables dip processing and spray coating. Further, the present invention relates to a novel plastisol which has good storage stability of sol viscosity and can exhibit physical properties that can be used under heating conditions at a lower temperature than vinyl chloride resin.

[0002]

2. Description of the Related Art Liquid dispersions prepared by mixing polyvinyl chloride resins and polymethyl methacrylate resins with plasticizers and various additives have been widely used as plastisols and organosols. The basic performance of plastisol is that the dispersion resin forms a flowable dispersion (sol) with a low number of plasticizer parts (for example, 60 parts by weight or less), and the viscosity increase when the sol is stored at 30 ° C. for 1 week. It is sufficiently small (for example, 50% or less) that there is no separation or precipitation, that the heat-gelled sheet is sufficiently plasticized (for example, 80 parts by weight of the plasticizer is added to the Shore-A hardness of 60 to 70), and There is no bleeding of the plasticizer, and the sheet obtained by heating and gelating a sol that does not use a diluent has both practical tensile strength (for example, 60 kg / cm ² or more) and elongation (for example, about 300% or more). is necessary. Polyvinyl chloride plastisols have conditions that fully satisfy all of the above performance due to the presence of plasticizers that can be effectively combined, and in addition to being low cost, they are used in the fields of automobiles, building materials, and electrical materials. It is used in a wide range of applications and has been used in the plastisol processing field for many years without being followed by other materials. However, in recent years, social interest in environmental problems has risen sharply, and there has been a strong demand for reduction of acid gas generation accompanying the incineration of wastes such as plastisol, and existing performance has not been impaired without impairing existing performance. There is an urgent need to develop materials that can replace halogenated resins.

[0003]

The object of the present invention is to provide a plastisol or an organosol which does not generate harmful acid gas associated with the incineration of a molded article, against the background of these requirements. The basic performance of the plastisol is that the dispersion resin forms a fluid dispersion (sol) with a low number of plasticizer parts, and the sol at 30 ° C.
Viscosity increase is sufficiently small when stored for 1 week, there is no separation or precipitation, the heat-gelled sheet is sufficiently plasticized, and there is no bleeding of the plasticizer, and no diluent is used. It is an object of the present invention to provide a plastisol in which a sheet obtained by heating and gelating a sol has both sufficient tensile strength and sufficient elongation.

[0004]

[Means for Solving the Problems] In order to obtain the above-mentioned requirements, the primary particle diameter and the particle diameter distribution of the resin particles and the wetting of the resin particle surface with the plasticizer are the main factors, and the primary particle diameter is Greatly depends on the method. Generally, the resin for plastisols is produced by emulsion polymerization or seed emulsion polymerization. In order to achieve the fluidity condition of, it is necessary to minimize the specific surface area with spherical resin particles, and in consideration of the sedimentation property of the resin particles in the plasticizer liquid, 2 to 5 μm.
Particles of m are optimal. Conventionally, many non-vinyl chloride plastisols are produced by emulsion polymerization, and since the primary particle size is small, a general-purpose plasticizer cannot be plastisol when added in an amount of 60 parts by weight or less based on 100 parts by weight of the resin.
There is a problem in that even if the amount is increased to 0 parts by weight, it is impossible to prepare a plastisol having a low viscosity that enables spray coating processing as in the case of vinyl chloride type. Next, the storage stability of the plastisol mentioned above depends on how to reduce the swelling of the resin particles by the plasticizer at room temperature. However, since the plasticizer is stable in the resin after heating and functions as a soft material, a plasticizer that is compatible or compatible with the resin particles is combined, so the essence of the plasticizer and the storage stability of viscosity are stable. And will have the property of being contrary to each other. In particular, when using a non-polar monomer having no polarization like vinyl chloride, this antinomy becomes more remarkable. In order to achieve both of these contradictory properties, it has been proposed that the resin particles have a core / shell structure so that the shell component is hard to be attacked by the plasticizer (Japanese Patent Publication No. 62-38).
No. 68), it is generally necessary that the amount of the shell component is about half of that of the core component in order to obtain a complete core / shell structure. There was a problem that it decreased compared to. In plastisol processing, a hard product may be produced by using an acrylate-based thermosetting plasticizer together, but in general, a plasticized soft product is intended in many cases. The plasticized material formed by the plasticizer used as the dispersion medium exhibits a softening effect with as little plasticizer as possible, and it is an essential condition as described above that the plasticizer does not bleed from the plasticized material after molding. . In general, those using a plasticizer that is compatible or compatible with the resin particles do not generally bleed, but for example, the entire resin particles are composed of only the shell composition that is difficult to be attacked by the plasticizer as described above. In this case, the heat-processed molded product always causes bleeding, and the plasticizer is separated during storage of plastisol. Particularly in the case of non-vinyl chloride type, there is a trade-off relationship in which it is more difficult to achieve both storage stability of plastisol viscosity and bleeding property of a plasticizer. With regard to the physical properties of tensile strength and elongation rate, taking a commercially available vinyl chloride-based and acrylic-based plastisol molded product as an example, the former is 80 parts by weight of the plasticizer and the tensile strength is 200 to 160 kg / cm ^2. The elongation is 350 to 450%, and the latter also has a tensile strength of 150 to 10 with 80 parts by weight of the plasticizer.
A soft material having 0 kg / cm ² and an elongation of 300 to 400% can be obtained. Most of the plastisol processing is often used in combination with the metal, fiber, paper, etc., which is the base material, by applying processing or dipping processing that takes advantage of the characteristics of liquid processing, rather than using it as a structural member, and particularly toughness is required. Although there are few fields, it is desirable that 60 to 80 parts by weight of the plasticizer has a tensile strength of 60 kg / cm ² or more and an elongation of about 300% or more. Further, as for the heat processing for expressing these physical properties, it is required that the temperature is as low as possible and the time is short. In the case of the above-mentioned commercially available vinyl chloride plastisol, heating at 180 ° C. for 10 minutes or more is required. Since, under the conditions of 140 ° C or less, each mechanical property is halved, some products are copolymerized with vinyl acetate for the purpose of imparting low temperature melting property, but these have increased viscosity during storage and their stability is insufficient. Is in a state. As mentioned above, most of the plastisol processing is used in combination with other base materials, but a resin that can be processed at low temperature is required from the viewpoint of preventing heat deterioration of the base material and reducing the cost of heating equipment and energy. ing. However, many plastisols that can be processed at low temperatures generally have insufficient storage stability of viscosity at 35 to 40 ° C. The present inventors have investigated the cause of the above problems, as a result of earnest research, the above-mentioned trade-off bottleneck, adopting a fine suspension polymerization method, introducing a polar monomer as a copolymerization unit, further To solve this by using the ionic crosslinking method,
At that time, it was found that a specific amount of the carboxyl group-containing monomer unit bonded to the polymer on the surface of the polymer particles is more effective in suppressing the viscosity increase with time of the sol viscosity. In the plastisol composition, a low-temperature processing method using a phthalic acid-based plasticizer has succeeded in producing a resin that has no bleed and can exhibit practical mechanical properties.

That is, in the present invention, 50 to 85 parts by weight of (A) (a) styrene monomer, 10 to 45 parts by weight of (b) monomer capable of radical copolymerization with styrene, and (c) carbon number. Radical-polymerizable unsaturated carboxylic acid monomer 3-8.
A plastisol composition comprising copolymer particles having an average primary particle diameter of 0.5 to 3 μm and (B) a phthalate ester-based plasticizer, obtained by finely suspension-polymerizing a monomer mixture consisting of 2 to 10 parts by weight. And (A) (a) styrene-based monomer 50 to 8
5 parts by weight, (b) 10 to 45 parts by weight of a monomer capable of radical copolymerization with styrene, and (c) 0.2 to 10 parts by weight of a radically polymerizable unsaturated carboxylic acid monomer having 3 to 8 carbon atoms. And a resin powder particle obtained by finely suspension-polymerizing a monomer mixture, which is obtained by ion-crosslinking a copolymer having a primary average particle diameter of 0.5 to 3 μm with a monovalent or divalent metal cation. B) A plastisol composition comprising a phthalate ester plasticizer, and further a plastisol composition in which the amount of carboxyl groups bonded to the particle surface of 100 g of the polymer in these plastisol compositions is 4 to 25 mmol. Is. Examples of the (a) styrene-based monomer used in the present invention include styrene and α-methylstyrene, and a benzene nucleus of these monomers substituted with a methyl group, an ethyl group, a propyl group or a butyl group. Monomer,
For example, vinyltoluene, isobutylstyrene, etc. can be used. In order to improve the physical properties of the (b) styrene polymer, particularly mechanical strength, heat distortion temperature, UV resistance, etc., these styrene-based monomers and radically copolymerizable monomers used in the present invention are used. Is what you use. Therefore, various monomers and copolymerization ratios can be appropriately selected depending on the use of the plastisol composition. That is, except for the styrene-based monomer and the radical-polymerizable unsaturated carboxylic acid monomer which are the components (a) and (c) of the present invention, an alkyl acrylate having 1 to 8 carbon atoms in the alkyl group or methacrylic acid is used. There is no particular limitation as long as it is a radical copolymerizable monomer such as an alkyl ester, vinyl ester, vinyl ether, vinyl cyanide, diene monomer, etc., and one or more of these monomers may be used in the present invention. It can be selected as the component (b). Examples of the acrylic acid alkyl ester and the methacrylic acid alkyl ester include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, t-butyl acrylate, n-hexyl acrylate. , Cyclohexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate,
Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate,
n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate and the like can be mentioned, and these may be used alone, You may use it in combination of 2 or more type. Of these, methyl methacrylate is particularly preferable.

On the other hand, as the vinyl ester, for example,
Vinyl acetate, vinyl propionate, vinyl myristate, vinyl oleate, vinyl benzoate and the like can be used. Acrylonitrile, methacrylonitrile, or the like can be used as vinyl cyanide.
Further, as the diene-based monomer, for example, butadiene,
Conjugated diene compounds such as isoprene, 1,3-pentadiene, cyclopentadiene, and dicyclopentadiene,
Non-conjugated diene compounds such as 1,4-hexadiene and ethylidene norbornene may be used. These may be used alone or in combination of two or more. Among these, butadiene and Isoprene is preferred. Further, in order to impart crosslinkability or curability after molding the plastisol composition of the present invention, a monomer having another functional group such as an epoxy group and an amino group, for example, glycidyl (meth) acrylate, 3,4 -Epoxycyclohexylmethyl (meth) acrylate, 2-aminoethyl (meth) acrylate, 3-aminopropyl (meth) acrylate, 2-aminobutyl (meth) acrylate,
3-aminobutyl (meth) acrylate, 4-aminobutyl (meth) acrylate, (meth) acrylamide,
N-2-aminoethyl (meth) acrylamide, N-2
Aminopropyl (meth) acrylamide, N-3 aminopropyl (meth) acrylamide and the like can be used as the component (b) of the present invention. The radical-polymerizable unsaturated carboxylic acid used in the component (c) of the present invention may be a monomer having 3 to 8 carbon atoms and having a free carboxyl group bonded to unsaturated bonded carbon. However, it can be used without particular limitation. For example, acrylic acid,
Unsaturated monocarboxylic acids such as methacrylic acid, ethacrylic acid, crotonic acid, cinnamic acid, maleic acid, itaconic acid,
Unsaturated dicarboxylic acids such as fumaric acid, citraconic acid, chloromaleic acid and their anhydrides and monomethyl maleate, monoethyl maleate, monobutyl maleate, monomethyl fumarate, monoethyl fumarate, monomethyl itaconate, monoethyl itaconate, itaconic acid Examples thereof include monoesters of unsaturated dicarboxylic acids such as monobutyl and derivatives thereof, and these may be used alone or in combination of two or more. Among these, acrylic acid and methacrylic acid are particularly preferable. The composition of the present invention comprises 50 to 85 parts by weight of the above (a) styrene-based monomer, 10 to 45 parts by weight of (b) a comonomer capable of radical copolymerization with styrene, and (c) 3 to 8 carbon atoms. The radically polymerizable unsaturated carboxylic acid monomer can be obtained by fine suspension polymerization of a monomer mixture having a mixing ratio of 0.2 to 10 parts by weight. The ratio of the component (a) and the component (b) was used in accordance with the desired physical properties of the desired resin for plastisol (b).
The component (b) is 1 depending on the kind of the component.
If it is less than 0 parts by weight, the physical properties are not sufficiently improved, and if it exceeds 45 parts by weight, it becomes difficult to simultaneously obtain the desired mechanical strength and plasticizing effect of the styrene-based plastisol composition.

When the resin particles prepared in plastisol are subjected to the swelling action of the plasticizer, the sol viscosity increases with the passage of time. If this is remarkable, not only is the use time restricted, but it is necessary to continue adjusting the viscosity during use. Occurs and is extremely difficult to use. Where the resin particles made only of the components (a) and (b) are subject to swelling by the plasticizer, the component (c) of the present invention causes the compatibility of the particles with the plasticizer to decrease, thereby causing swelling. Has a preventive effect. When the content of the component (c) is less than 0.2 part by weight, the effect of modifying the surface of the particles by ionic crosslinking or free carboxyl groups is hardly seen.
When the amount is more than 0 parts by weight, the effect of modifying the surface of the particles is not improved as compared with the case where the amount is less than that, and rather the original mechanical properties of the base resin are often deteriorated. There are three places where the component (c) exists as a part of the polymer as a result of the polymerization reaction: the resin particle surface layer, the inside of the resin particles, and the aqueous phase (serum) of the polymerization medium. The prevention of swelling of the plasticizer is a function of and. Particularly, it is effective for the stability of the sol viscosity with time that the carboxyl groups are present on the particle surface in an amount of 4 to 25 mmol per 100 g of the polymer. When the amount of carboxyl groups on the particle surface is less than 4 mmol / 100 g of resin, it is necessary that the whole particle be incompatible with the plasticizer in order to prevent the sol viscosity from increasing with time. It is not preferable because it shows the property. On the other hand, if the amount exceeds 25 mmol / 100 g resin, the particle surface becomes too poorly compatible with the plasticizer, resulting in a sol that is easily separated.
The component (c) is allowed to polymerize a large amount in the surface layer portion of the particles,
In addition, making the interior of the particles compatible with the plasticizer is effective in preventing the sol viscosity from increasing with time and preventing bleeding of the molded product. As a method therefor, when styrene is used as the component (a) and methacrylic acid is used as the component (c),
A method in which a comonomer having a hydrophilicity higher than that of styrene such as methylmethacrylate is used as the component (b), and the component (c) is distributed at a high concentration therein and polymerized at the interface side with water, A method of polymerizing the component (c) so that the outer layer portion of the particles is formed in the latter half of the polymerization reaction by selecting a comonomer having a relatively low copolymerization reactivity with styrene as the component (c). There is a method of intermittently or continuously supplying the component (c) to the polymerization vessel in the latter half of the polymerization reaction, which can be appropriately selected. When the method of (2) is adopted, it is necessary to use the component (b) in a large amount of about 40 parts by weight or more. When taking the method described in (1), the copolymerization monomer reactivity ratio described in "Polymer Data Handbook (Basic Edition)" edited by The Polymer Society of Japan, pp. 444-459, published by Baifukan in 1986 can be referred to. In the case of adopting the method (1), the addition of the component (c) is started at the time when the polymerization conversion rate of the initially charged monomer is 60 to 95%, and the monomer is continuously or intermittently supplied. The supply liquid may be a component (c) alone or a mixture of the component (c) and a part of the component (a), a part or all of the component (b), and the like. In addition, it is not necessary to add the surfactant and the polymerization initiator along with the addition of (c).

The amount of carboxyl groups bonded to the polymer on the particle surface of the plastisol composition of the present invention can be measured by a conductivity titration method. This is JOHN HE
N, J. Colloid Interface Sci.
Vol. 49, p. 475 (1974) "Determi
national of Surface Carboxy
l Groups in Styrene / Itaco
nic Acid Copolymer Latex
s ". In the plastisol composition of the present invention, the amount of carboxyl groups bonded to the polymer on the particle surface in 100 g of the polymer is measured by a conductivity titration method, and If the value is less than 4 mmol, the resin particles may be a useful plastisol resin, so that a polymer having a delicate balance as follows is preferable. The composition is difficult to control, that is, the polymer inside the particles must not be too compatible with the plasticizer so that the sol viscosity does not rise over time, yet it does not bleed the plasticizer after molding. For this reason, a certain degree of compatibility is required.On the other hand, when the above value exceeds 25 mmol, the surface of the resin particles does not fit into the plasticizer regardless of the internal polymer composition. In the fine suspension polymerization method used in the present invention, an oil-soluble radical initiator is used as the 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-butyl peroxydicarbonate,
Peroxydicarbonates such as di-2-ethylhexyl peroxydicarbonate, peroxyesters such as t-butylperoxypivalate and t-butylperoxyneodecanoate, or organic peroxides such as acetylcyclohexylsulfonyl peroxide and disuccinic acid peroxide. Oxides, and even 2,2'-
Azobisisobutyronitrile, 2,2'-azobis-2-
Examples thereof include azo compounds such as methylbutyronitrile and 2,2′-azobisdimethylvaleronitrile. These initiators may be used alone or in combination of two or more, and the usage amount thereof is appropriately selected depending on the kind and amount of the monomer, the charging system, etc. It is selected in the range of 0.001 to 5.0 parts by weight per 100 parts by weight of the body. A surfactant is usually used in the fine suspension polymerization method. Examples of the surfactant include alkyl sulfate salts such as sodium lauryl sulfate, sodium myristyl sulfate, sodium dodecylbenzenesulfonate, alkylarylsulfonates such as potassium dodecylbenzenesulfonate, sodium dioctylsulfosuccinate, dihexylsulfosuccinate. Sulfosuccinate salts such as sodium acid salt, ammonium laurate, fatty acid salts such as potassium stearate, polyoxyethylene alkyl sulfate ester salts, anionic surfactants such as polyoxyethylene alkylaryl sulfate ester salts, sorbitan monooleate, Sorbitan esters such as polyoxyethylene sorbitan monostearate, polyoxyethylene alkyl ethers, polio Examples include nonionic surfactants such as cyethylene alkyl phenyl ethers, glycerin alkyl esters and polyoxyethylene alkyl esters, and cationic surfactants such as cetylpyridinium chloride and cetyl trimethyl ammonium bromide. One kind may be used, or two or more kinds may be used in combination, and the amount thereof is usually 0.0 per 100 parts by weight of the monomer used.
It is selected in the range of 5 to 5 parts by weight, preferably 0.2 to 4.0 parts by weight.

An emulsification aid may be added for the purpose of protecting and stabilizing the emulsion droplets of the monomer obtained by the homogenization treatment. The additive has 10 to 24 carbon atoms.
Higher alcohols having alkyl groups of 10 to 2 carbon atoms
A higher fatty acid having an alkyl group of 0, a fatty acid ester of a higher alcohol having 4 to 18 carbon atoms and a higher fatty acid having 4 to 18 carbon atoms can be used. These may be added in an amount of 0 to 5 parts by weight, preferably 0.5 to 2 parts by weight, based on 100 parts by weight of the total monomers. In the fine suspension polymerization method of the present invention, first, in an aqueous medium, the oil-soluble initiator, the total amount of monomers, the surfactant, and an emulsion of higher fatty acids and higher alcohols used as desired Auxiliary agents and other additives are added and premixed, and then homogenized by a homogenizer to adjust the particle size of oil droplets. Examples of the homogenizer used for the homogenization treatment include a colloid mill, a vibration stirrer, a two-stage high pressure pump, a high pressure jet from a nozzle or an orifice, and ultrasonic stirring. Furthermore, controlling the particle size of oil droplets is affected by controlling the shearing force during homogenization, stirring conditions during polymerization, type of reactor, amount of surfactants and additives, etc. Suitable conditions can be selected by various preliminary experiments. Next, the liquid homogenized in this manner is sent to a polymerization vessel and heated slowly with stirring, usually at 30 to 80 ° C.
The polymerization is carried out at a temperature in the range. At this time, when the radically polymerizable unsaturated carboxylic acid monomer is excluded during the premixing, the polymerization conversion ratio of the initially charged monomer is 60.
The addition of the radically polymerizable unsaturated carboxylic acid monomer to the polymerization vessel is started at about 95% of the time, and thereafter, the particles are continuously or intermittently dropped to coat the existing particles to carry out polymerization. In this way, there is almost no formation of agglomerates and the average particle size is 0.0
A latex in which polymer particles of about 5 to 3 μm are uniformly dispersed is obtained. The monovalent or divalent metal cation added as the ionic crosslinking agent used in the present invention may be a metal capable of ionically crosslinking the free carboxyl group of the copolymer of the present invention. It can be added to the latex system after the polymerization reaction to form ionic crosslinks by these metal cations.
In the plastisol composition of the present invention, when a trivalent metal cation is used as an ionic crosslinking agent to ionically crosslink between carboxyl groups in the polymer, the resulting ionic crosslinked product has a temperature of 1 at which the crosslinking is dissociated. Since it is higher than in the case of divalent and divalent metal cations, a gelled product having insufficient physical properties and poor gelation is provided unless the heat molding temperature is raised. Further, even a monovalent cation such as ammonium ion which is not a metal has little effect of suppressing increase in viscosity of plastisol with time. The monovalent or divalent metal cation used in the present invention is not particularly limited, and examples thereof include potassium cation, sodium cation, magnesium cation, calcium cation, barium cation, iron cation, nickel cation, copper cation, zinc cation. , Cesium cations, tin cations, chromium cations, lead cations, strontium cations, and the like. These may be used alone or in combination of two or more. Among these, particularly preferred are potassium cation, zinc cation, and calcium cation.

The ionic crosslinked product constituting the particles of the component (A) of the present invention can be produced by adding a monovalent or divalent metal cation or a metal cation supplier which produces the same to the above copolymer. it can. The monovalent or divalent metal cation supplier may be added directly as it is or in the form of a solution such as an aqueous solution. Examples of the monovalent or divalent metal cation supplier include oxides, hydroxides, phosphates, carbonates, octylic acid, stearic acid, oleic acid, caprylic acid, formic acid, and amber of monovalent or divalent metal cations. Acid, erucic acid, linolenic acid, palmitic acid, propionic acid, acetic acid, adipic acid, butyric acid,
It is possible to use salts of organic acids such as naphthenic acid and thiocarboxylic acid, acetylacetone salts, ethoxide and methoxide alcoholates. In particular, a monovalent metal hydroxide or carboxylate is effective in terms of reaction efficiency and easily deformed during heat molding. The monovalent and divalent metal cation donors do not require heating for a relatively long time in carrying out the crosslinking reaction like the trivalent or higher valent metal cation donors, and within a few minutes at room temperature in the solution. It is desirable because it has a characteristic that an ionic cross-linking reaction is possible.
In addition, when a radically polymerizable unsaturated carboxylic acid is copolymerized in an aqueous polymerization solution and a hydroxide of a monovalent metal is added thereto, a room temperature region between the carboxyl group present on the particle surface and the metal cation supplier is obtained. An ion exchange reaction is carried out in a short time, while an ionic crosslinking reaction is carried out with other carboxyl groups on the particle surface via cations. In the above-mentioned ionic crosslinked product, a part or the whole of the free carboxyl group is ionized to form a carboxyl anion, which forms an ionic bond by using a monovalent or divalent metal ion as a counter cation, and is monovalent even with other carboxyl groups. An ionic bond is formed through a cation cluster or a divalent cation. The ionic crosslinking rate can be adjusted by the amount of the metal cation supplier added. In the above-mentioned ionic crosslinking reaction, a monovalent or divalent metal cation or a metal cation supplier thereof can be used in an excessive amount over the theoretical amount. The presence of this ionic cross-link can be easily analyzed by measuring the absorption of the carboxylate group by infrared absorption spectrum, quantifying the metal ion, and measuring the degree of swelling in the solvent. The dissociation property of ionic crosslinks can be confirmed by differential thermal analysis, and the density can be confirmed by measuring the degree of swelling. Although the latex can be used as it is depending on the application, a known treatment such as salting out or spray drying is usually performed, and the polymer is taken out as a solid. The molecular weight of the polymer is appropriately adjusted by the reaction temperature and the molecular weight modifier according to the purpose. Generally, in plastisols of vinyl chloride or acrylic resins,
As a polymerization method for obtaining a resin having a particle size distribution suitable for plastisol, emulsion polymerization or seed emulsion polymerization is performed.
However, when these polymerization methods are used in the method for producing a plastisol resin mainly composed of a styrene-based monomer of the present invention, a sol having a high viscosity is obtained, which is not suitable. In the styrene-based plastisol composition of the present invention, the dispersibility in the plasticizer is good only by the fine suspension polymerization method described above, plastisol can be easily formed with a small number of plasticizers, and 80 wt% without using a diluent. It is possible to obtain a plastisol having a low viscosity of, for example, a shearing rate of 1500 / sec or more and 1000 centipoise or less, which enables spray processing with a plasticizer of a part.

In the composition of the present invention, a plasticizer is used as the component (B). The plasticizer is not particularly limited, and is conventionally used as a plasticizer for vinyl chloride resin plastisols, such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, di- (2-ethylhexyl) phthalate, di-n-octyl phthalate. , Diisobutyl phthalate, dihexyl phthalate,
Phthalic acid derivatives such as diheptyl phthalate, diisononyl phthalate, diphenyl phthalate, diisodecyl phthalate, ditridecyl phthalate, diundecyl phthalate, dibenzyl phthalate, butylbenzyl phthalate, dinonyl phthalate, dicyclohexyl phthalate, dimethyl isophthalate, di- (2- Isohexyl) isophthalate, isophthalic acid derivatives such as diisooctyl isophthalate, di-2-ethylhexyl tetrahydrophthalate, di-n-octyl tetrahydrophthalate, tetrahydrophthalic acid derivatives such as diisodecyl tetrahydrophthalate, di-n-butyl adipate, di Adipic acid derivatives such as-(2-ethylhexyl) adipate, diisodecyl adipate, diisononyl adipate, di- ( -Ethylhexyl) azelate, diisooctyl azelate, azelaic acid derivative such as di-n-hexyl azelate, di-n-butyl sebacate, sebacic acid derivative such as di- (2-ethylhexyl) sebacate, di-n-butyl maleate, Maleic acid derivatives such as dimethyl maleate, diethyl maleate and di- (2-ethylhexyl) malate, fumaric acid derivatives such as di-n-butyl fumarate and di- (2-ethylhexyl) fumarate, tri- (2-ethylhexyl) ) Trimellitic acid derivatives such as trimellitate, tri-n-octyl trimellitate, triisodecyl trimellitate, triisooctyl trimellitate, tri-n-hexyl trimellitate and triisononyl trimellitate,
Pyromellitic acid derivatives such as tetra- (2-ethylhexyl) pyromellitate and tetra-n-octylpyromellitate, triethyl citrate, tri-n-butyl citrate, acetyltriethyl citrate, acetyltri- (2-ethylhexyl) citrate Itaconic acid derivatives such as citric acid derivatives, monomethyl itaconate, monobutyl itaconate, dimethyl itaconate, diethyl itaconate, dibutyl itaconate, di- (2-ethylhexyl) itaconate, butyl oleate, glyceryl monooleate, diethylene glycol mono Oleate and other oleic acid derivatives, methyl acetyl ricinoleate, butyl acetyl ricinoleate, glyceryl monoricinoleate, diethylene glycol monoricinoleate and other ricinoleic acid derivatives , Stearic acid derivatives such as n-butyl stearate, glycerin monostearate, diethylene glycol distearate, other fatty acid derivatives such as diethylene glycol monolaurate, diethylene glycol dipelargonate, pentaerythritol fatty acid ester, triethyl phosphate, tributyl phosphate, tributyl phosphate. Phosphoric acid derivatives such as-(2-ethylhexyl) phosphate, tributoxyethyl phosphate, triphenyl phosphate, cresyl diphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, tris (chloroethyl) phosphate, diethylene glycol dibenzoate, dipropylene glycol Dibenzoate, triethylene glycol dibenzoate, triethylene glycol Ruji -
(2-ethylbutyrate), triethylene glycol di- (2-ethylhexoate), glycol derivative such as dibutylmethylene bisthioglycolate, glycerol monoacetate, glycerol triacetate, glycerol derivative such as glycerol tributyrate, epoxy Soybean oil, epoxy butyl stearate, epoxy hexahydrophthalic acid di-2-ethylhexyl, epoxy hexahydrophthalic acid diisodecyl, epoxy triglyceride, epoxidized octyl oleate, epoxy derivative such as epoxidized decyl oleate, adipic acid polyester Polyester plasticizer such as sebacic acid polyester, phthalic acid polyester, partially hydrogenated terphenyl, adhesive plasticizer, diallyl phthalate, acetic acid Although such polymeric plasticizers such as Le monomer or oligomer can be cited, it is preferred that the phthalate in these. These plasticizers are 1
One kind may be used, or two or more kinds may be used in combination, and a plasticizer in which a polymer compound such as rubber or resin is dissolved may be optionally used. The blending amount of the plasticizer as the component (B) in the composition of the present invention is usually selected in the range of 40 to 250 parts by weight, preferably in the range of 60 to 120 parts by weight, per 100 parts by weight of the particles of the component (A). Is selected in. In the plastisol of the present invention, a filler such as calcium carbonate can be used as an extender in an amount of 30 to 100 parts by weight based on 100 parts by weight of the resin. Even in such a case, a particle diameter of 10 obtained by suspension polymerization of a monomer having the same composition as that used in the fine suspension polymerization using a water-soluble polymer such as gelatin, methyl cellulose, or polyvinyl alcohol as a suspension dispersant. So-called blending resins consisting of ~ 100μ resin particles can be replaced with 10-40% by weight of the plastisol resin of the present invention.
Further, in some cases, by adding 10 parts by weight or less of a hydrocarbon-based diluent comprising a low boiling point mineral oil to 100 parts by weight of the total resin, a plastisol having a low viscosity capable of spray processing can be similarly obtained. You can

[0012]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples. Table 1 shows the blending of the raw material monomers, the average particle size of the particles, the viscosity of the plastisol, and the physical properties of the sheet obtained from the plastisol in the examples and comparative examples.

[0013]

[Table 1]

Note 1) Suspension refers to fine suspension polymerization, and emulsion refers to emulsion polymerization or seeded emulsion polymerization.

[0015]

[Table 2]

Note 2) Indicates the number of parts of the monomer added during the polymerization reaction.

[Table 3]

[0017]

[Table 4]

[0018]

[Table 5]

The physical properties shown in Table 1 and the preparation of plastisol were carried out as follows. (1) Average particle size of primary particles The average particle size of single particles at the end of the polymerization reaction of the copolymer resin or at the end of the reaction of the ionic crosslinked product is a 10,000 times magnified photograph taken with a transmission electron microscope. The particle diameter of about 1000 particles was measured and averaged to obtain the primary particle average particle diameter. The average particle size of secondary particles containing agglomerates after drying was 50 g of powder after removing coarse particles through a sieve having openings of 250 μm and carbon black 50 as an antistatic agent.
mg was added, and a JIS standard sieve was used to perform a sieve analysis under vibration to obtain a particle size of 50% by weight. (2) Plastisol viscosity and aging index (AI) Brookfield (BM) type rotational viscometer [Tokyo Keiki
Manufactured by Co., Ltd.) under the conditions of a temperature of 25 ° C. and a relative humidity of 60%. 4 at 60 rpm. Plastisol was stored at 25 ° C and the temperature was changed to 25 ° C on the 7th day.
It is an index value obtained by dividing the viscosity measured at a humidity of 60% for 1 hour by the viscosity immediately after the preparation of plastisol. (3) Physical properties After applying plastisol to a thickness of 0.3 mm on a glass plate, it is heated in a hot air circulation oven at 120 ° C for 20 minutes to prepare a physical property measurement sheet, and tensile strength, elongation rate, hardness and bleeding property are prepared. The transparency was measured. Measurement of tensile strength is 200 mm
The bleeding property was evaluated by visual observation after leaving the sheet in an atmosphere having a temperature of 25 ° C. and a humidity of 60% for 30 days, and evaluated according to the following criteria. ◯: No bleeding was observed Δ: Very slight bleeding was observed ×: Bleeding was observed Further, the transparency was evaluated according to the following criteria by visually observing the physical property measurement sheet. ◯: Transparent Δ: Semi-transparent ×: Opaque Further, the production of particles composed of an ionic crosslinked product and the preparation of plastisol were carried out as follows. (4) Preparation of plastisol 100 parts by weight of resin particles for plastisol consisting of each type and amount of each component shown in Table 1 and di-2-ethylhexyl phthalate (DOP) in the amount shown in Table 1 were vacuum degassed. It was put into a planetary mixer all at once and mixed for 20 minutes to prepare a plastisol. (5) Amount of carboxyl groups on the surface of polymer particles per 100 g of polymer A latex containing the polymer Ag was placed in a beaker, and a 0.5N aqueous sodium hydroxide solution was added dropwise with stirring with a stirrer to adjust the pH to 12. To do. Next, 0.1 N hydrochloric acid aqueous solution is added dropwise at intervals of 30 seconds while measuring the electric conductivity by 0.5 ml. The electric conductivity decreases, reaches a minimum point, then starts increasing, and a drop amount a milliliter of the hydrochloric acid aqueous solution until reaching the first inflection point is obtained. The equivalent number of the carboxyl groups on the surface of the polymer particles, that is, the number of moles per 100 g of the polymer is calculated by the following formula. 0.1 × (a / 1000) × (100 / A) = a / 100A [mol]

Example 1 200 parts by weight of distilled water, 32 parts by weight of methyl methacrylate monomer, 3 parts by weight of methacrylic acid monomer, and 1 carbon atom were placed in a 10-liter stainless steel premixing vessel having two-stage blades.
2.0 parts by weight of linear higher alcohol of 8 and 0.5 parts by weight of sodium alkylbenzene sulfonate and 65 of styrene monomer
Into the parts by weight, 0.3 parts by weight of dibenzoyl peroxide was charged in advance, the mixture was mixed at a temperature of 30 ° C. for 1 hour, the suspension formed by stirring was passed through a homogenizer, and then another part having two-stage blades was used. It was transferred into a pressure-resistant container made of stainless steel of 10 liters, and fine suspension polymerization was carried out at a temperature of 75 ° C. 0.4 part by weight of a 5.6 wt% aqueous solution of potassium hydroxide was added to the latex obtained by the polymerization reaction, and the temperature was adjusted to 1 at 23 ° C.
Mix for 0 minutes. Then, this was spray-dried in a nitrogen gas stream at 170 ° C. to obtain resin particles for plastisol.
The average primary particle size obtained here was 2.3 μm.
100 parts by weight of the resin particles obtained here and 80 parts by weight of di2-ethylhexyl phthalate were put into a vacuum degassing planetary mixer all at once and mixed for 20 minutes to prepare a plastisol. This plastisol has a low initial viscosity even at a shear rate of 1500 / sec or more even at a low shear rate close to stationary, and has good storage stability for a long period of time, and has a viscosity that enables easy coating and spraying. is doing. The sheet obtained by heat-treating this sol at 120 ° C. for 10 minutes is transparent and is plasticized without causing bleeding, and has sufficient mechanical strength for use as a soft coating material. It was Example 2 In the polymer latex prepared in Example 1, zinc was used in place of potassium as the cation for ionic crosslinking. That is, 1.3 parts by weight of zinc acetate as a cation supplier was added to the latex obtained by polymerization, and the latex obtained by stirring at 23 ° C. for 60 minutes was dried and sol-adjusted in the same manner as in Example 1. . The obtained plastisol showed the same performance as the sol of Example 1. Example 3 Instead of styrene used in the polymerization of Example 1, α-methylstyrene was used. The conditions of polymerization, ionic crosslinking, drying, and sol adjustment were the same as in Example 1. The viscosity characteristics and sheet properties of the obtained plastisol showed the same results as in Example 1. Example 4 In the example in which acrylonitrile was used in place of the methyl methacrylate used in the polymerization of Example 1, polymerization, ionic crosslinking, drying and sol adjustment were carried out under the same conditions as in Example 1.
The viscosity of the obtained plastisol hardly changed with time.
The sheet properties showed the same results as in Example 1. However, the color tone changed to yellow under the heating condition of 120 ° C. × 10 minutes for producing the sheet.

Example 5 N-butyl acrylate was used in place of the methyl methacrylate used in the polymerization of Example 1. Polymerization, ionic crosslinking, drying, and sol preparation were carried out under the same conditions as in Example 1.
The viscosity of the obtained plastisol hardly changed with time.
The sheet physical properties tended to be softer than those of Example 1. Example 6 When the latex obtained by the polymerization of Example 1 was dried without adding potassium hydroxide as a cation supplier and sol adjustment was performed, the initial viscosity of plastisol increased as compared with Example 1. A aging index (AI) of 1.6 was obtained. With regard to the physical properties of the sheet, the same results as in Example 1 were shown. In this example, the cation supplier was not added, but sodium ions were present in the emulsifier of the polymerization auxiliary material, and it is considered that this contributed to ionic crosslinking, and no addition of unsaturated carboxylic acid monomer was performed. Compared to (Comparative Example 8),
There was an improvement in AI. Example 7 200 parts by weight of distilled water, 28 parts by weight of methyl methacrylate monomer, and linear higher alcohol having 18 carbon atoms were added to a 10-liter stainless steel premixing container having two-stage blades.
0.3 parts by weight of dibenzoyl peroxide was previously added to 0.5 parts by weight of sodium benzenebenzenesulfonate and 64 parts by weight of styrene monomer, and the mixture was mixed at a temperature of 30 ° C. for 1 hour, and then the emulsion was homogenized. And then
The mixture was transferred to another 10-liter stainless reactor having a two-stage blade, and fine suspension polymerization was started at a temperature of 75 ° C. From the time when the polymerization conversion rate of the charged monomers was 75%, the polymerization reaction was continued while continuously supplying a mixed solution of 6 parts by weight of styrene monomer and 2 parts by weight of methacrylic acid monomer to the reactor.
After 1 hour and 15 minutes from the end of this supply, the reaction was terminated by cooling the reaction time to 8 hours and 15 minutes. The polymerization conversion rate for all monomers was 96%. To the latex obtained by the polymerization reaction, a 5.6% aqueous solution of potassium hydroxide was added to 0.6.
170 parts by weight was added and mixed at a temperature of 23 ° C. for 10 minutes.
Spray drying was carried out in a nitrogen stream at ℃ to obtain resin particles. The average primary particle diameter was 1.8 μm. The ratio of unsaturated carboxylic acid monomer units on the surface of the particles was 0.81 parts by weight as measured by the potentiometric titration method.

Comparative Example 1 In the example obtained by adding 0.5 parts by weight of aluminum hydroxide as a cation supplier to the latex obtained by the polymerization of Example 1, an ionically crosslinked latex was prepared by stirring at 40 ° C. for 60 minutes. Drying and sol preparation were carried out in the same manner as in Example 1. The initial viscosity of the obtained plastisol was significantly higher than that of Example 1. Although the sol viscosity AI was good, the low temperature gelation property was slightly lowered, the tensile strength of the heat-formed sheet was lowered, and bleeding of the plasticizer occurred. Comparative Example 2 To the latex obtained by the polymerization of Example 1, 0.25 part by weight of ammonium hydroxide was added as a cation supplier.
The latex ion-crosslinked by stirring at 23 ° C. for 10 minutes was dried and the sol was adjusted in the same manner as in Example 1.
The initial viscosity of the obtained plastisol was equivalent to that of Example 1, but the AI decreased to nearly 2. Also, the tensile strength of the heat-formed sheet was reduced. Comparative Example 3 200 parts by weight of distilled water and 1 total of 3 kinds of monomers in Table 1 were placed in a 10 liter stainless steel pressure vessel having two-stage blades.
00 parts by weight and sodium alkylbenzene sulfonate 0.5
Parts by weight and tetrasodium salt of ethylenediaminetetraacetic acid
1 part by weight and 0.05 part by weight of potassium persulfate were charged, and emulsion polymerization was carried out at a temperature of 75 ° C. 0.4 parts by weight of a 5.6 wt% aqueous solution of potassium hydroxide was added as a cation supplier to the latex having an average particle size of 0.2 μ obtained by polymerization.
Ionic crosslinking was performed at 10 ° C for 10 minutes. The following spray drying and sol adjustment were performed in the same manner as in Example 1. However, in contrast to Examples 1 to 7 in which sol mixing was possible with 60 parts by weight of di-2-ethylhexyl phthalate, in this example, 10 was used.
It was difficult to form a smooth sheet with a knife coater even with plastisol prepared by adjusting the amount of plastisol required to be 0 parts by weight or more and 120 parts by weight because of its high viscosity. Comparative Example 4 Using the latex obtained by the polymerization of Comparative Example 3 as a seed, emulsion polymerization was further performed. That is, instead of 200 parts by weight of distilled water of Comparative Example 3, 25 parts by weight of the seed latex having a solid content of 30% and 230 parts by weight of distilled water were used, and three kinds of monomers, sodium alkylbenzenesulfonate and ethylenediaminetetraacetic acid were used. The same amount of the tetrasodium salt and potassium persulfate described in Comparative Example 3 were charged, and emulsion polymerization was performed at 75 ° C.
Ion crosslinking, spray drying, and sol preparation were performed on the latex obtained by polymerization and having an average particle size of 0.5 μm in the same manner as in Comparative Example 3. In this example, 80 parts by weight or more of a plasticizer was required to enable sol mixing, and even a plastisol prepared with 100 parts by weight was difficult to form a smooth sheet with a knife coater because of its high viscosity. Comparative Example 5 In the example in which the second seed polymerization was carried out using the latex having a solid content concentration of 30% obtained by the polymerization of Comparative Example 4 as a seed, the seed latex obtained in Comparative Example 4 was 35 as in Comparative Example 4. Seed emulsion polymerization was carried out under the same conditions as in Comparative Example 4 using 100 parts by weight of distilled water and 230 parts by weight of distilled water. The obtained latex having an average particle diameter of 1.1 μ was subjected to ionic crosslinking, spray drying and sol adjustment in the same manner as in Comparative Example 3.
The plastisol prepared by using 100 parts by weight of the obtained resin and an equal weight of the plasticizer had a higher initial viscosity and an insufficient AI. However, the sheet properties were sufficiently good.

Comparative Example 6 Comparative Example 5 is the same as Comparative Example 5 except that the latex obtained by the polymerization of Comparative Example 5 was used as a seed for the third seed polymerization.
The seed latex with a solid content of 30% obtained in
Seed emulsion polymerization was carried out under the same conditions as in Comparative Example 4 using 100 parts by weight of distilled water and 230 parts by weight of distilled water. Three
After the polymerization was repeated, the cumulative total of the intermittent reaction times was about 28 hours. The obtained latex having an average particle size of 1.5 μm was subjected to ionic crosslinking, spray drying and sol adjustment in the same manner as in Comparative Example 3. The obtained resin reached a level where the viscosity could be evaluated with 80 parts by weight of a plasticizer, but it was difficult to form a smooth sheet with a knife coater because of its high viscosity. Comparative Example 7 When the sol was adjusted using a resin obtained by drying the latex obtained by the polymerization of Comparative Example 5 without adding potassium hydroxide, it was found that the viscosity could be evaluated with 100 parts by weight of the plasticizer. However, the viscosity was as high as that of Comparative Example 6. Comparative Example 8 Fine suspension polymerization was carried out under the same conditions as in Example 1 using only 70 parts by weight of styrene and 30 parts by weight of methyl methacrylate, and 0.4 part by weight of a 5.6 wt% aqueous solution of potassium hydroxide was added. Then, spray drying and sol adjustment were performed. The obtained resin reached a level where viscosity evaluation was possible with 130 parts by weight of the plasticizer, but it solidified after 3 days. Comparative Example 9 Instead of 65 parts by weight of styrene and 32 parts by weight of methyl methacrylate of Example 1, 25 parts by weight of styrene and 72 parts by weight of methyl methacrylate were changed, and all other conditions were the same as in Example 1. The obtained resin became a plastisol having a low viscosity with 80 parts by weight of a plasticizer, had a good AI and a high sheet physical property, but the sheet was opaque and had a large hardness and marked bleeding. Comparative Example 10 Instead of 65 parts by weight of styrene and 32 parts by weight of methyl methacrylate in Example 1, 87 parts by weight of styrene and 10 parts by weight of methyl methacrylate were changed, and all other conditions were the same as in Example 1. The obtained resin became a plastisol having a low viscosity with 100 parts by weight of the plasticizer and had a good AI, but the tensile strength of the sheet was extremely low. Comparative Example 11 Fine suspension polymerization was carried out under the same conditions as in Example 1 using 60 parts by weight of styrene, 39.9 parts by weight of methyl methacrylate and 0.1 part by weight of methacrylic acid as monomers, and potassium hydroxide was added to the obtained latex. Example 1 with the addition of 0.02 parts by weight
Ionic crosslinking, spray drying and sol preparation were performed in the same manner as in. The viscosity of the obtained resin could be evaluated with 100 parts by weight of the plasticizer, but the viscosity was so high that it could not be formed into a smooth sheet with a knife coater. Comparative Example 12 Fine suspension polymerization was carried out under the same conditions as in Example 1 using 65 parts by weight of styrene, 27 parts by weight of methyl methacrylate and 8 parts by weight of methacrylic acid as monomers, and 1.0 part by weight of potassium hydroxide was added to the obtained latex. Was added to carry out ionic crosslinking, spray drying and sol adjustment in the same manner as in Example 1. The resulting resin becomes a low viscosity plastisol with 80 parts by weight of plasticizer,
The AI was also good, but the heat-formed sheet was opaque and the bleeding of the plasticizer was remarkable.

[0024]

EFFECTS OF THE INVENTION The plastisol composition of the present invention has no fear of pollution because it does not generate a halogen compound during combustion.
There are advantages of obtaining a styrene-based plastisol composition having a low viscosity, good long-term storage stability at room temperature, little bleeding of a plasticizer in a molded sheet, and good physical properties of tensile strength and elongation.

Claims (3)

[Claims] 1. A) (a) styrenic monomer 50-85
Parts by weight, (b) 10 to 45 parts by weight of a monomer capable of radical copolymerization with styrene, and (c) 0.2 to 10 parts by weight of a radically polymerizable unsaturated carboxylic acid monomer having 3 to 8 carbon atoms. A styrene-based plastisol composition comprising copolymer particles having a primary average particle diameter of 0.5 to 3 μm and (B) a plasticizer, obtained by finely suspension-polymerizing a monomer mixture. 2. A) (a) styrenic monomer 50 to 85
Parts by weight, (b) 10 to 45 parts by weight of a monomer capable of radical copolymerization with styrene, and (c) 0.2 to 10 parts by weight of a radically polymerizable unsaturated carboxylic acid monomer having 3 to 8 carbon atoms. Resin powder particles obtained by finely suspension-polymerizing a monomer mixture, obtained by ion-crosslinking a copolymer having a primary average particle diameter of 0.5 to 3 μm with a monovalent or divalent metal cation, and (B )
A styrene-based plastisol composition comprising a plasticizer. 3. The styrene-based plastisol composition according to claim 1, wherein the amount of carboxyl groups in 100 g of the polymer is 4 to 25 mmol on the surface of the polymer particles.