JPS5984931A - Production of thermoplastic resin particle - Google Patents

Abstract

PURPOSE:To produce expandable thermoplastic resin particles having improved heat resistance, by incorporating a specific styrene-maleic anhydride copolymer resin with a specific compound and a vinyl aromatic monomer in a specific proportion, and reacting them in the presence of a polymerization catalyst and a foaming agent. CONSTITUTION:20-50pts.wt. styrene-maleic anhydride copolymer resin, containing 20-30wt% maleic anhydride component, and having 10-250 average polymerization degree, 1-18pts.wt. compound of the formula RX (X is a functional group reactive with dicarbonyloxo group; R is an aliphatic residue having one double bond), e.g. glycidyl acrylate, and a polymerization catalyst, e.g. benzoyl peroxide, are dissolved in 79-32pts.wt. vinyl aromatic monomer, e.g. styrene, and the resultant solution is suspended in an aqueous medium and reacted preferably at 80-90 deg.C for 2-12hr. A foaming agent, e.g. propane, is added to the suspension during or after the reaction to produce the aimed thermoplastic resin particles.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing p,% malleable resin particles.

More specifically, in this invention, the maleic anhydride component is
20-50 parts by weight of a styrene-maleic anhydride copolymer resin having an average degree of polymerization of 10-250 and containing ~80 parts by weight, 2R
X (wherein X is a functional group that reacts with a dicarbonyloxo group,
1 to 18 parts by weight of a compound represented by R (R is an aliphatic residue having one double bond) and a polymerization catalyst are dissolved in 79 to 82 parts by weight of a vinyl aromatic monomer, and this solution is suspended in an aqueous medium. This invention relates to the i'J system of thermoplastic resin particles, which comprises making the thermoplastic resin particles cloudy, reacting them, and adding a blowing agent during or after the reaction to obtain foamable π-plastic resin particles.

Although polystyrene resins are widely used as resins for molding materials and foaming materials, they have a low heat distortion temperature and cannot be used in applications that require heat resistance.

On the other hand, styrene-maleic anhydride copolymer resin has a high heat distortion temperature, but in order to uniformly distribute the maleic acid component in the molecule and make it into a polymer, the control of the reaction is extremely difficult. : L <A complicated method was required, and the resin produced had to have a high 1iTli. By the way, styrene-maleic anhydride copolymer resins with low polymerization degrees, such as an average degree of polymerization of 10 to 250, can be obtained relatively easily with various blending ratios of styrene/maleic anhydride, and are widely used in a variety of applications. Generally used.

In view of the above-mentioned current situation, the inventors of the present invention have developed a thermoplastic resin with excellent heat resistance (heat distortion temperature) by utilizing the easily available styrene-maleic anhydride copolymer resin with a low degree of polymerization. The research was based on the idea that it could be exploited. As a result, the hydrothermal maleic acid component is 20 to 80% by weight.
It contains a styrene-maleic anhydride copolymer resin with a low degree of polymerization, a compound having a functional group and a double bond that can react with a carboxylic acid anhydride in the same molecule (herein referred to as a bonding monomer), and a vinyl aromatic The group monomers are mixed and treated in the presence of a polymerization mediating medium, and the above-mentioned It was discovered that a thermoplastic resin with a high deformation temperature can be obtained by polymerizing monomers, and after further study, the present invention was arrived at.

In this invention, a styrene-maleic anhydride copolymer resin containing 20 to 80% by weight of a maleic anhydride component and having an average degree of polymerization of 10 to 250 is used. Styrene-maleic anhydride copolymerization - 1 If the content of maleic anhydride component in the fat exceeds 30% by weight, it will dissolve in the aromatic monomer F, f6 <, 20% by weight oLxDtJ> in the thermoplastic resin produced. This is undesirable because the maleic anhydride component contained in the resin is reduced and the desired heat resistance cannot be obtained.

A styrene-maleic anhydride copolymer resin with an average degree of polymerization of 10 to 250 is used because maleic anhydride and styrene monomer undergo an alternating copolymerization reaction of 1:1, and if the resin has a low degree of polymerization, This is because by changing the initial mixing ratio of maleic anhydride and styrene, the copolymer resin containing h1 maleic anhydride component can be obtained extremely easily and in large quantities.

The vinyl aromatic monomers used in this invention are styrene, σ-methylstyrene, ethylstyrene,
Chlorostyrene, bromostyrene, vinyltoluene, vinylxylene, isopropylxylene, etc., or a mixture of two or more of them, together with a vinyl aromatic monomer containing 50% by weight or more of these vinyl aromatic monomers. A mixture with a polymerizable single RF substance such as acrylonitrinopemethyl methacrylate or methyl acrylate may be used.

The weight μ ratio of the styrene-maleic anhydride copolymer resin and the vinyl aromatic monomer is 79
The amount is 20 to 50 parts by weight of the styrene-maleic anhydride copolymer resin to 82 parts by weight. If the amount of copolymer resin used is less than this range, the final thermoplastic resin obtained will have a low heat distortion temperature, which is undesirable, and if the amount of copolymer resin used is more than this range, the copolymer resin will not dissolve. This is not preferable because it takes a long time and becomes highly viscous, making it difficult to control the reaction.

As the bonding monomer, a compound represented by the formula RX (where X is a functional group that reacts with a dicarbonyloxo group, and R is an aliphatic residue having one double bond) is used.

The functional group in the definition of 2RX means a group that can react with the dioxocarbonyl group of the maleic anhydride moiety in the styrene-furnace water maleic acid copolymer resin. Examples of such functional groups include hydroxy groups, amide groups, and epoxy groups. The hydroxy group or amide group is preferably bonded to the vinyl group through one or two carbon atoms. ′=! The epoxy group may be bonded to the vinyl group via an oxygen atom or a carbon atom. Specific compounds include allyl glycidyl ether, glycidyl acrylate, glycidyl methacrylate, allyl alcohol, N-n-butyloxymethyl acrylamide, and the like.

These compounds are generally known as disease molecule modifiers, and compounds similar to these are used.

The amount of the bonding monomer used in this invention is 1 to 50 parts by weight of the suguruen-hydrothermal maleic acid copolymer resin.
The amount is 18 parts by weight (this corresponds to about 5 to 100 molti based on the maleic anhydride component of the styrene-maleic anhydride copolymer resin).

If the amount of the bonding monomer used is less than this range, the resulting resin will have poor thermal properties, and if it exceeds this range, no improvement in the thermal properties will be observed. Examples of the polymerization catalyst used in this invention include benzoyl peroxide, t
Organic oxides such as tert-butyl perbenzoate, lauroyl peroxide, tert-butylperoxy-2-ethylhexanate, tert-butyl peroxide, azobisisobutyronitrile, azobisdimethylvaleronitrile, etc. Examples include azo compounds.

In this invention, first, the above-mentioned styrene-maleic anhydride copolymer resin, binding monomer, and polymerized hornworm medium are dissolved in a vinyl aromatic monomer, and this is suspended in an aqueous medium and reacted. A dispersing agent is usually used for suspension in an aqueous medium. As dispersants, compounds such as partially saponified polyvinyl alcohol, polyacrylates, polyvinylpyrrolidone, carboxymethyl cellulose, methyl cellulose, calcium stearate, and ethylene bisstearamide can be used once a month.

The treatment reaction in this invention is carried out by heating and stirring at a temperature of 65 to 95°C, preferably about 80 to 90°C, for 2 to 12 hours.
The reaction is completed by heating at 20-140°C and stirring for 10 minutes.

Under these conditions, attack of the functional group It is thought that polymerization with double bonds in monomers and intermolecular crosslinking due to these reactions occur.

In this invention, the thermoplastic resin particles further include a blowing agent.

The blowing agents used in this invention include easily volatile blowing agents, such as aliphatic hydrocarbons such as propane, n-butane, 1-butane, n-pentane, 1-pentane, and n-hexane, cyclopentane, Examples include cycloaliphatic hydrocarbons such as cyclohexane, halogenated hydrocarbons such as methyl chloride, ethyl chloride, dichlorodifluoromethane, chlorodifluoromethane, and trichlorofluoromethane. These blowing agents are generally used in a ratio of 8 to 40 parts by weight per part of the thermoplastic resin particles. Further, a small amount of an organic solvent such as toluene or xylene may be used in combination.

The blowing agent may be added at any time during or after the reaction. Preferably, the product particles are impregnated after the reaction. To impregnate the thermoplastic particles with a blowing agent after the reaction is complete,
For example, do you suspend II ■ clouding agent in an autoclave? This is carried out by suspending thermoplastic resin particles in a suspended liquid, heating the mixture, and pressurizing the foaming agent. The suspending agent used in the aqueous suspension is added to prevent the thermoplastic resin particles from binding or coalescing with each other during impregnation with the blowing agent, and is added as a dispersing agent. In addition to the above-mentioned organic metal compounds, inorganic compounds consisting of fine powder hardly soluble in water, such as calcium pyrophosphate, calcium phosphate, calcium carbonate, magnesium carbonate, magnesium phosphate, magnesium birophosphate, and magnesium oxide, can be used.

In the method of this invention, when an inorganic compound is used as a suspending agent, it is preferable to use a surfactant such as sodium dodecylbenzenesulfonate. These dispersants are generally used in an amount of 0.001 to 5% by weight based on water.

The expandable thermoplastic resin particles obtained as described above are
Separate from water, wash and dry as appropriate before use.

The expandable thermoplastic resin particles obtained by this invention have better heat resistance than polystyrene, and can be easily obtained in large quantities with desired particle sizes.

Next, Example M will explain the invention.

Example 1 Contents In a fl 51 polymerization vessel, 20005' of water and 60 f of aqueous solution of partially saponified polyvinyl alcohol were added. Insert the
Furthermore, styrene-external water maleic acid copolymer resin 8 has a maleic anhydride content of 25% by weight and an average degree of polymerization of 19.
00, benzoyl peroxide 4. O5', tert-butyl perbenzoate 1.2y, glycidyl methacrylate
) A mixed solution of 800 f styrene monomer dissolved in 900 f was added, and the temperature was raised to 90°C while stirring with a stirring blade for 100 revolutions. After maintaining the temperature at 90°C for 7 hours, the stirring was increased to 250 rpm and then to 180°C.
After heating, the reaction was maintained for 2 hours to complete the reaction. Note 9
During the reaction period at 0° C., 261 portions of an aqueous solution of partially saponified polyvinyl alcohol were added every hour. The resin obtained here was pearl-like particles having a distribution of 70 between 18 and 80 mesh using a sieve of J Engineering S standard. Further, after being crushed in hot toluene at 130°C for 4 hours, the amount of insoluble matter was 76% by weight and the softening temperature was 105°C.

Example 2 Implementation ['ll 1 f (0fC resin 12005', water 2800f, metathesis method magnesium birophosphate 4.8P
A dihydric aqueous solution of sodium dodecylbenzenesulfonate (10 liters) was poured into an autoclave containing 8 Gff of toluene and 51 liters of rust. Butane 12 in a sealed state while stirring.
The temperature was raised to 85° C. and maintained for 14 hours.

Thereafter, the mixture was cooled to 80° C. to obtain beads containing a foaming agent.

After washing, dehydrating, and drying the beads, they were placed in a sealed container and stored at 15° C. for 24 hours. When the foamable beads obtained here were foamed with steam at 100°C, the result was 0.0
Expanded particles were obtained with a bulk density of 80 kg/l. After leaving the foamed particles in a room for 24 hours, the mold was slightly overfilled and molded with steam at 0.8 kg2/d (gauge pressure). 90°C of the obtained foam molded product
When it was left in an air-circulating heating tank for one week, it shrunk by 8.8 times in one direction compared to its original size.

Comparative Example Polymerization was carried out under the same conditions as in Example 1 except that styrene monomer 3002 was used instead of glycyldyl methacrylate 3002 (the softening point of i'+1 fat was 95°C. Beads containing a foaming agent were obtained under the same method by Tosaku. When these beads were foamed with steam at 95°C, foamed particles having a bulk density of 0.028 kg// were obtained. However, these foamed particles were However, it was not possible to obtain a sufficient molded body.

Example 8 A resin obtained by reacting under the same conditions as in Example 1 except that the ratio of glycidyl methacrylate and styrene monomer was changed as follows showed the following softening temperature.

Glycidyl methacrylate Styrene monomer Softening temperature (Y>
('0600 600 107
800 900 105120
1080 10812
1188 980
1200 95 Example 4 20005' of water and 50 g of a 2% by weight aqueous solution of partially saponified polyvinyl alcohol were put into a reaction vessel with contents y<r+t, and the content of maleic anhydride was 25% by weight in advance, and the average polymerization A mixed solution of 460 g of styrene-maleic anhydride copolymer (8.25 g of benzoyl peroxide, 1.62 g of t-butyl perbenzoate, 8505 g of glycidyl methacrylate) dissolved in 18001 styrene monomer was introduced. Then, the temperature was raised to 90° C. while stirring with a stirring blade of 100 revolutions. After feeding and holding at a temperature of 90°C for 7 hours, the stirring was increased to 250 rpm for 1 i'
Raise the temperature to 10°C and then keep it at a temperature of 130°C for about 2 hours.
The reaction was completed within 1 hour. During the reaction time at 90°C, polymerization was carried out by adding 25y of a 2% by weight aqueous solution of partially saponified polyvinyl alcohol every hour. In this way, the obtained polymer was sieved with a sieve of 16 to 80
They were pearl-like particles with a distribution of 78 inches between the meshes.

Further, after 4 hours of immersion in hot toluene at 180°C, the amount of insoluble matter was 98% by weight. The soft irritability of these particles was 106°C.

Representative Patent Attorney Shintabe Nogawa 253-

Claims (1)

[Claims] 1. Maleic anhydride component 20-80:g+,'f
20 to 50 parts by weight of a styrene-maleic anhydride copolymer resin having an average degree of polymerization of lO to 250, containing ijr%, formula R
x (in the formula, XH reacts with dicarbonyloxo
A compound 1-18 (where R is an aliphatic residue having one double bond) and a polymerization catalyst are dissolved in vinyl aromatic monomer 79-82N, and this solution is dissolved in an aqueous solution. 112 and reacted, at which time,
A method for producing resin particles having a heat degree of 9° 1, which is characterized in that foamable @ijk plastic resin particles are obtained by adding a blowing agent during or after the reaction.