JPS6063235A - Expandable thermoplastic resin beads and its manufacture - Google Patents

Abstract

PURPOSE:To obtain the titled resin beads capable of giving in good moldability foam-molded body free from tertiary foaming even at high temperatures, with excellent heat and solvent resistance, by incorporating alpha-methylstyrene/acrylonitrile copolymer with both readily volatile foaming agent and specific amido compound. CONSTITUTION:The objective resin beads can be obtained by incorporating (A) a polymer consisting of (i) 10-80wt% of alpha-methylstyrene, (ii) 5-50wt% of acrylonitrile and (iii) 0-70wt% of a third compound selected from styrene, methyl methacrylate, vinyltoluene and t-butylstyrene, with (B) 2-15wt% of a readily volatile foaming agent and (C) 0.01-0.5wt% of an amido compound insoluble in water with a melting point >=100 deg.C (pref. stearoamide, methylenebisstearoamide). The whole process is as follows: The component (A) is subjected, using a bifunctional organic peroxide as initiator, to suspension polymerization at 80-130 deg.C. The component (C) being added and the component (B) being impregnated during or prior to the polymerization.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to expandable thermoplastic resin particles which have excellent heat resistance and solvent resistance, as well as good foamability and moldability, and an industrially advantageous manufacturing method thereof. be.

As expandable synthetic resin particles, expandable polystyrene resin particles are well known, and by using these particles, a molded foamed article can be easily obtained at low cost. However, since the monomer constituting the polymer is styrene, the foam molded product can be used for heat insulation of relatively high-temperature pipes, insulation for roofs, automobile abductions, heating for solar systems, etc.
It has the disadvantage that it cannot be used in applications that require heat resistance.

In addition, when used in conjunction with other parts, especially in automatic tombstones, etc., it is difficult to select an adhesive because the solvent resistance is poor.
It also has the disadvantage of being f1ff.

Therefore, in order to obtain expandable thermoplastic resin particles having sufficient heat resistance and solvent resistance for practical use, the present inventors found that alpha-methyl It was thought that it was necessary to obtain copolymer resin particles having a methyleff ratio of 102 or more and containing 5% or more of acrylonitrile, and to impregnate these resin particles with an easily volatile blowing agent. However, based on this point of view, conventionally alpha methyl styrene was used in large amounts as described in 1. -, di-butyl perbenzoate, di-butyl peroxide, and other organic peroxides are used as polymerization initiators.
In methods using these initiators, it is necessary to use them in extremely large amounts regardless of the polymerization temperature, and therefore the resulting copolymer has an extremely low degree of polymerization and is impregnated with an easily volatile foaming agent and subjected to foaming heat "i".
J plastic resins t) "R and pears have extremely poor foaming properties, resulting in not only a satisfactory foamed molded product but also a weak molded product.Furthermore, these initiators If the amount used is reduced in order to increase the degree of polymerization using a polymer, a so-called dead end polymerization will occur, and a high conversion rate cannot be obtained industrially, so that a satisfactory foamed molded product is f) short. Furthermore, if an organic peroxide such as penzoyl peroxide is used, a copolymer with a high conversion rate that can be used industrially even at an appropriate polymerization temperature can be obtained. ).

On the other hand, emulsion polymerization is a method for obtaining alpha-methylstyrene-acryloni-1-vine yarn copolymer with a high degree of polymerization and a high conversion rate. As seen in Japanese Patent Application Laid-Open No. 57-65735, the manufacturing method requires an extremely complicated process of emulsion polymerization, coagulation into pentyl chloride, and impregnation of the resulting pellet with a blowing agent. This method has the drawback that not only is the viscosity higher, but also that the resultant resin contains a large amount of emulsifiers, coagulants, etc., resulting in only products with poor foamability, strength, etc.

As a result of extensive research, the present inventors have discovered a suspension polymerization method that allows a copolymer with a high degree of polymerization and a high conversion rate to be obtained even when using a large amount of alpha methylstyrene, and the resulting copolymer resin particles are easily produced. By impregnating the particles with a volatile blowing agent, we succeeded in obtaining expandable thermoplastic resin particles with excellent heat resistance. However, such foaming heat t + J plastic resin f
After pre-foaming the foam, molding is performed to obtain a foam molded product, and when the foam molded product is left under high temperature, the surface layer of the molded product changes even though there is almost no dimensional change in the foam molded product. Due to the large expansion of the foamed rod forming the part, unsightly unevenness (hereinafter referred to as tertiary foaming) occurs on the surface of the molded product, and the aesthetic appearance is significantly impaired. In view of these drawbacks, the present inventors conducted further intensive research and found that by making an amide compound with a certain hR exist in the particles, 11iI thermoplastic particles with no tertiary foaming even under high temperature conditions and with almost no dimensional deterioration. The present invention was completed by discovering expandable thermoplastic resin particles and a method for producing the same that provide excellent foam molded articles.

That is, the present invention provides that (1) the monomers constituting the polymer are
10-80% of alpha methylstyrene, 5-50% by weight of acrylonitrile, and 0-70% by weight of at least one compound selected from K7 tyrene, methyl methacrylate, vinyltoluene, and t-butylstyrene. , 2 to 15% by weight of a readily volatile blowing agent, and 0.0% of an amide compound that is insoluble in water and has a melting point of 100'C or higher.
(2) 10-80% by weight of alpha methylstyrene, 5-50% by weight of acrylonitrile, including styrene, methyl methacrylate, vinyl 1-luene, - at least one compound selected from butylstyrene, using monomers in an amount of 0 to 70% by weight and 11%, using a difunctional organic peroxide as an initiator, at a polymerization temperature of 80 to 130%; '
In a method for obtaining expandable thermoplastic resin particles, the copolymerization is carried out by suspension polymerization in C, and a readily volatile blowing agent is added during or after the polymerization, to obtain expandable thermoplastic resin particles. The method of producing expandable thermoplastic resin particles is characterized in that an amide compound having a melting point of 100° C. or higher is added in an amount of 0.01 to 0.5% by weight.

The amount of alpha methylstyrene used in the present invention is 1
It is determined by the desired heat resistance and expansion ratio in the range of 0 to 80% by weight, but if it is less than 10% by weight, the heat resistance property will be poor.
The effect of - is no longer seen, and when the concentration exceeds 80%, the polymerization conversion rate is low, and a large amount of 1i-mer remains in the resin.
1Ii, fever worsens. 100 with 50 times foamed form
'C's heat resistance f? 8, it is necessary to use 20-50% by weight of alpha methylstyrene, and 5-15% by weight.
In order to obtain a heat resistance of 110"C with a double foam molded product, 50~
80% by weight alpha methylstyrene should be used.

Furthermore, acrylonitrile used in the present invention is necessary to improve the polymerization conversion rate of the composition and to exhibit oil resistance, and if it is less than 5% by weight, the polymerization conversion rate of the composition will be low and the oil resistance will be improved. It is not preferable because it will not be effective in sex.

Furthermore, even if the amount is more than 50% by weight, the polymerization conversion rate does not change and the resin becomes yellowish brown, which is not desirable.

Examples of p-isomers other than alpha-methylstyrene and acrylonitrile include one or more of styrene, methyl methacrylate, vinyltoluene, and t-butylstyrene.
2 can be used as appropriate.

Easily volatile blowing agents used in the present invention include aliphatic hydrocarbons such as propane, butane, and pentane, cycloaliphatic hydrocarbons such as cyclopenkune, cyclopenkune, and cyclohexane, and 1-lik V1 fluoromethane and dichlorofluoromethane. , cyclodifluoromethane, methyl chloride, dichlorotetrafluoroethane, and ethyl chloride. The amount of these blowing agents to be used varies depending on the desired expansion ratio of the foamed molded product, but if it is contained in an amount of 2 to 15% by weight, it is possible to obtain a foamed molded product that is 2 to 100 times larger. It is.

Further, the present invention provides, in addition to the composition mentioned above, an amide compound which is insoluble in water and has a melting point of 100'C or more.
The amide compound is characterized by containing 1 to 05% by weight, and is effective in controlling tertiary foaming when the foamed molded product is placed under high temperature conditions. No significant effect was observed when the content was less than 0.0.1% by weight, and particles containing more than 0.05% by weight had poor moldability when molded after pre-foaming, resulting in a smooth surface. Conditions for obtaining a molded article ``1'' are very narrow or completely absent and are not suitable. Preferred amide compounds used here include stearamide, methylene bis stearamide, and ethylene bis nutearamide.

Therefore, as a method for obtaining such expandable thermoplastic resin particles, a single-prefecture polymerization method is employed.

In the emulsion polymerization method, as mentioned earlier, the process is complicated.
'11 There is a cost increase due to the process of polymerization and a decrease in quality due to the contamination of emulsifiers and coagulants. It is inferior to the suspension polymerization method in terms of complexity.

Dispersants used in the suspension polymerization include organic dispersants such as polyvinyl alcohol, polyvinylpyrrolidone, and methyl sulfurose, and inorganic dispersants such as tricalcium phosphate, calcium pyrophosphate, sodium silicate, lead oxide, and magnesium carbonate. However, when an inorganic dispersant is used, the effect of the dispersant is significantly improved by using an anionic surfactant such as sodium alkylbenzenesulfonate or a-onfinsulfonate sorter.

Selection of the initiator used in the present invention is important in order to efficiently obtain a resin with a high degree of polymerization and a high polymerization conversion rate. If the polymerization conversion rate is low and more than 5% of the monomer remains in the resin, it is difficult to obtain a satisfactory foamed molded product, and even if a foamed molded product is barely obtained,
This results in extremely poor heat resistance. From this point of view, as the initiator to be used, a difunctional organic peroxide is used, especially one whose half-life temperature is 60'
C to 120'c and which generates t-but-1-xylyl and radicals are preferred. An initiator that satisfies these conditions and can be used in practice is di-t-butylperoxyhexahydroterephthalate-1-1,1.
, 1-butylperoxy3.3.5-I.limethylcyclohexane, di-t-butylperoxyazele-1., 2.5-dimethyl-25-bis(2-ethylhegizanonylperoxy) Oxy)hekey IJ-7,1,1-t-butylperoxycyclohexane, 1,3-bis-(t-butylperoxyiso-10vir)benzene, 2
．． 2-c(t-butylperoxy)butane, 4,4-
Examples include di-butylperoxyvaleric acid n-butyl ester, di-t-butylperoxytrimethylacipe I, and the like. These initiators should be used in an amount of 01 to 20% by weight based on the total amount of monomers; if it is less than 01% by weight, an industrially practical polymerization conversion rate may not be obtained at all or a long time may be required. This results in extremely poor productivity. 2. When the amount of QTR is % or more, the molecular weight decreases significantly and 1. M517 cannot be added to foam molding, or even if foam molding can be done, the strength is too high.
Only a foam molded product with poor quality can be obtained.

The polymerization temperature when using an initiator in the present invention is 80°C.
The temperature is preferably 133 DEG C. to 133 DEG C. At 80 DEG C., the polymerization conversion rate becomes extremely low, and if the temperature exceeds 130 DEG C., the molecular weight decreases and a satisfactory foamed molded product is not obtained.

Here, the timing of adding the above-mentioned amide compound is as follows:
It may be added at any time from before the start of the polymerization until the polymerization conversion rate reaches 50% during the polymerization, and the addition method may be any method of adding it all at once, in portions, or continuously into the system.

Even if these amide compounds are added to the polymerization system after the polymerization conversion rate reaches 50%, they will not be uniformly incorporated into the particles, which is not preferable. Further, the above-mentioned easily volatile blowing agent may be added at any time during or after the polymerization.

On the other hand, in the present invention, when the purpose is a highly foamed molded product, solvents such as 1-luene, xylene, ethylbenzene, heptane, octane, styrene, alpha-methylstyrene, ac-1-no-2-1-IJ)Ly It is preferable to incorporate monomers such as 7,1 fat particles, or plasticizers such as phthalate esters and adipate esters into the foamable thermoplastic 7,1 fat particles. Methods for incorporating these solvents and plasticizers include a method in which they are mixed with monomers in advance and polymerized, and a method in which they are impregnated simultaneously with the impregnation with a blowing agent. In addition, as a method for containing the monomer,
Although unreacted monomers will remain after polymerization, it is important to control the remaining amount.

The amount of these solvents and plasticizers used is preferably 3% by weight or less.

The thus obtained foamable thermoplastic resin t:1. The foam is pre-foamed to a desired magnification using a heating medium such as steam or hot air, then filled into a mold that can be closed but cannot be sealed, and heated again using a heating medium such as steam to form the desired shape. It can be made into a heat-resistant foam molded article having the following properties.

The present invention will be explained below with reference to Examples.

Example 1 100 parts by weight of pure water was placed in an autoclave with a stirrer.
Tricalcium phosphate 0.2 parts, 1
-Decylbenzenurfonic acid sodium 0.003 heavy H
% parts by weight, 0.1 parts by weight of ethylene bisstearamide' with stirring, followed by monomers consisting of 30 parts by weight of Alf, 20 parts by weight of acrylonitrile, and 50 parts by weight of styrene; 1-toluene 10 parts by weight, 1,1-cy-butylperoxy 3.3.5-1~
0.3 parts by weight of limethylcyclohexane was mixed and added into the autoclave, and polymerization was carried out at +00° C. for 8 hours until 11 hours. The polymerization conversion rate of the composition determined by tQ was 994%. Then add 10 parts by weight of butane and heat at 100'C for 8
Foaming agent impregnation was carried out for an hour. The resulting foaming heat riJ
The plastic resin was designated as resin (A). After pre-foaming the resin (A) to a nominal magnification of 50 times by heating it with steam, it is filled into a mold that can be blocked but cannot be sealed, and heated with steam to form a foam of 45cmX'+OcmX2c.
A plate-shaped foamed molded product of m was obtained.

The plate-shaped foam molded product was placed in a hot air soaking dryer at 100°C.
The dimensional change rate with respect to the initial dimension after leaving it for a week, and
The state of tertiary foaming on the surface of the molded product was investigated and shown in Tables 1 and 2.

Examples 2 and 3 Expandable thermoplastic resin particles obtained in the same manner as in Example 1 except that ethylene bis stearamide was used, stearamide and ethylene bis stearamide were used as resin (B). , resin (C). These resins were evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Example 1 Expandable thermoplastic resin particles were obtained in the same manner as in Example 1, except that the ethylene bis-sulfuramide was not added at <7?A. Table 1 shows the results of the same evaluation as in 1.

Examples 4 and 5 Expandable thermoplastic resin particles obtained in the same manner as in Example 1 except that the fit of ethylene bisstearamide was 0.05 part by weight and 1 part by weight were added to the resin, respectively. and resin (F).

The obtained resin was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

Comparative Example 2 Foaming heat was obtained in the same manner as in Example 1, except that the amount of ethylene bisstearamide was 0.6 parts by weight and the amount of tribasic calcium phosphate added as a suspension stabilizer was 0.5 parts by weight. The plastic resin particles were prepared as a resin ((1). An attempt was made to mold the obtained resin in the same manner as in Example 1, but a satisfactory molded product could not be obtained.

Table 1 *10: No tertiary foaming △: Tertiary foaming is quite self-evident 2 Procedural drawing book March 3rd, Showa Z, 3P date 4'6' ¥F□5.・1 ゎ、I、□１０７． or '
f,, J7+1, 411 items displayed 11β Sum 58 years E jT iY Day I No. 17164.
(Relationship with 3rd Lj Juice 6th applicant (1, location), I, 92I'112, Nakayuki, Kita-ku, Hanshi,
Mr. No. 1 Name (first name (6・) Kanebuchihi”;”fgo1゛,:1
, Representative Nagisa of the ceremony, Takashi B1, Atsu 4, agent 58 L1 Ij of the amendment order 6 Number of inventions increased by the amendment 8 Contents of the amendment (1 ni"1nlff4<'→--t
J + jf to m) welfare five floor 3 (2) Detailed explanation of the invention 1
Okai, page 5, lines 7-8, [turny butyl...
...Butyl perbenzony 1-1lt-r teranyalyzotyl peroxybenzoate, taanyalybutyl peroxyacetate, etc. are under pressure.

Song: Page 12 of the same page is missing to 3 rA of the same page, line 3, “Bifunctionality I”
I-1-0 "machine ..., especially 10 hours ... is preferable"
11k) A bifunctional compound with a half-life temperature of 60 to 120°C.
organic peroxide, in particular the t-butI-xy radical
@,! Is it good or bad to cause something? +I? Do 11 mi.

Above (Attachment) Claims (1) The monomer JJk constituting the polymer is
Rustyrene 10-80% to FFI, Acrylonitol 5%
~50% by weight, and ~70% by weight of at least one compound derived from styrene, late methyl methacrylate, vinyltoluene, t-glylstyrene,
Easily volatile 11 foaming agent 2 to 15% by weight and Ami-F modified product 0.0, non-bathable in water and having a melting point of 100°C or higher. O1～
Expandable thermoplastic resin particles containing 0.5% by weight and 11%.

(2) The amide compound is of at least one type selected from stearamide, methylene bis stearamide, and ethylene bis stearamide. is the nf plasticity tree one-finger particle.

(3) The optical N-type plastic resin particles are 0.5 to 3.0
The foaming heat according to claim 1 or 2, which contains 1% of a solvent! IJ! r/J
lII 41#J fat particles.

(4) Alpha methylstyrene lO~80'ff1f
fi%, 5 to 50% by weight of acrylonitrile, and at least one type selected from styrene, methyl methacrylate, vinyltoluene, and t-butylene, and a compound of 0 to 1 above.
Using a single 11L body at a usage rate of ~70% by weight, 1
Starting with a difunctional organic peroxide having a half-life temperature of 60 to 120°C, z [f is subjected to suspension polymerization at a temperature of 80 to 130°C, and the copolymerization is carried out during or after the polymerization.
A method of impregnating foaming raw thermoplastic raw resin particles with a readily volatile blowing agent Cj), which is insoluble in water at the initiation of polymerization or during polymerization, and has a melting point of 100
℃ and second Ami!゛A method for producing expandable thermal IIJ plastic 1 raw resin particles, characterized by adding 01 to 0.5% by weight of a compound (11 to 0.5% by weight, where 11 is 100).

(5) The compound according to claim 3, wherein the amyl' compound 4>t consists of at least one type of stearamide, methylene bis stearamide, and ethylene bis stearamide. Effervescent heat i+J sov! A method for producing sex sphere particles.

(6) Bifunctional A] The foamable thermal i2J plastic resin particles according to Section 3 or Section 554 of Claim J1, in which the shallow peroxide stops t-but-1-xy radicals. Production method.

(7) The difunctional organic peroxide is a sheet t-butyl/”-
, l-xyhexahydroterephcrate, t-butylperoxyazele-1-1l, l-cy, monobutylperoxy'a, 3,5-trinotylrecyclohexane. A method for producing photofoamable thermoplastic resin particles according to claim 3 or 4.

(8) 0.5 to 3.0% by weight in photofoamable thermoplastic resin particles
Any one of claims 3 to 6 containing a solvent of
Method for manufacturing raw resin particles.

Claims (8)

[Claims] (1) The monomers constituting the polymer are alpha methylstyrene 10-80 TJ%, acrylonitrile 5-5%
0% by weight, and further 0 to 70% by weight of at least one compound selected from styrene, methyl methacrylate, vinyltoluene, and t-butylstyrene, and the easily volatile blowing agent 2
~15% by weight and insoluble in water, Ga+'7! I
Amide compounds o, oi~05 with a t point of 100'C or more
Expandable thermoplastic resin particles containing % Juban. (2) The expandable thermoplastic resin particles according to claim 1, wherein the amide compound is composed of at least one of stearamide, methylene bis stearamide, and ethylene bis stearamide. (3) Foaming 1t1. The expandable thermoplastic resin resin according to claim 1, wherein the thermoplastic resin particles contain 05 to 60% by weight of a solvent. (4) Alpha methylstyrene 10-80% weight (;(
%, acrylonitrile 5-50% by weight, further styrene,
Polymerization using a monomer of at least one compound selected from methyl methacrylate, vinyltoluene, and t-butylstyrene at a usage rate of 0 to 70% by weight, using a difunctional organic peroxide as an initiator. Copolymerization is carried out by suspension polymerization at a temperature of 80 to 130'C, and during or after the polymerization, an easily volatile blowing agent is impregnated and foaming heat [iJ In the method of obtaining a plastic resin resin, polymerization initiation 6 '+J or during polymerization,
Foaming thermal foam characterized by adding an amide compound o, o i~05% by weight (assuming the total amount of monomers is 100) which is insoluble in water and has a rarest point of io'c or more. Method for producing plastic resin particles. (5) Foamed f'l: thermoplastic resin particles according to claim 6, wherein the amide compound is composed of at least one of stearamide, methylene bis-stearamide, and ethylene-vinutearoamide. manufacturing method. (6) The method for producing expandable thermoplastic resin particles according to claim 6 or 4, wherein the difunctional organic peroxide generates t-butoxy radicals. (7) The difunctional organic peroxide is di-butylperoxyhexahydroterephthalate-1, t-butylperoxyazele-1, and 1.1-di-t-butylperoxyfiltrate. , 3. 5-1-Remethylcyclohexane. 3. The method for producing a foamable thermoplastic resin molding according to claim 6 or claim 4, which comprises at least one kind of 5-1-limethylcyclohexane. (8) The method for producing expandable thermoplastic resin particles according to any one of claims 6 to 6, wherein the expandable thermoplastic resin particles contain 0.5 to 60% by weight of a solvent.