JPS6377963A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To provide the title resin compsn. which has excellent moldability and gives molded products having excellent transparency, resistance to weather and impact, etc., by mixing two methacrylate thermoplastic polymers having different reduced viscosities with a specified rubber-contg. polymer. CONSTITUTION:0.1-20pts.wt. thermoplastic polymer (A) having a reduced viscosity higher than 0.1l/g, composed of 50-100wt% methyl methacrylate and 50-0wt% copolymerizable vinyl monomer, is mixed with 5-99.9pts.wt. rubber- contg. polymer (B) obtd. by polymerizing a monomer mixture contg. 50-100wt% methacrylic ester in the presence of an elastomeric copolymer composed of 50-99.9wt% alkyl acrylate, 0.1-10wt% crosslinking monomer, etc. and a 0-94.9 pts.wt. thermoplastic polymer (C) having a reduced viscosity not higher than 0.1l/g obtd. by polymerizing a monomer mixture contg. 50-100wt% methacrylic ester having a 1-4C alkyl group in such a proportion that the aggregate is 100pts.wt.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an impact-resistant resin composition that has excellent transparency, weather resistance, and extremely excellent moldability.

[Conventional technology]

Methacrylic resin is widely used commercially because of its elegant appearance and excellent weather resistance, but it has poor impact resistance.
This may cause problems during handling.

For this reason, various methods have been proposed for introducing rubber to improve impact resistance. However, in most cases, the elegant appearance and weather resistance of methacrylic resin are impaired, making it difficult to put it into practical use.

For example, the method disclosed in Japanese Patent Publication No. 45-26111 is known as a method for improving impact resistance without relatively compromising transparency; Since it is a combination, a product with good transparency can be obtained in the early stage of production, but when used outdoors, it quickly becomes cloudy and cracks, resulting in a decrease in transparency and impact resistance.

In addition, Japanese Patent Publication No. 18298/1983 proposed a method of blending a graft copolymer mainly composed of acrylic acid ester with methacrylic resin, resulting in a resin composition with excellent transparency, weather resistance, and impact resistance. It is being

[Problem that the invention seeks to solve]

Various impact-resistant methacrylic resins that have been proposed in the past show excellent transparency and impact resistance when injection molded as a molding material, but there is a strong demand for even better moldability, and T-die etc. When it is made into a film using , it has the disadvantage that it is difficult to form a thin product and tends to have uneven thickness.

[Means for solving problems]

In view of the above facts, the inventors of the present invention have developed a method that does not impair the properties of methacrylic resin, namely colorless transparency and weather resistance.
As a result of intensive research into resin compositions with excellent moldability,
The present invention was achieved by discovering that excellent moldability can be obtained by blending a specific copolymer.

That is, the gist of the present invention is that the following thermoplastic polymer [I] 0.1 to 20 parts by weight, rubber-containing polymer [II] 5 to 99.9 parts by weight, thermoplastic polymer El )
It consists of 0 to 94.9 parts by weight, [I].

Cl3. (1) The thermoplastic resin composition contains 100 parts by weight in total.

[I] Thermoplastic polymer methyl methacrylate 50-100! % and 0 to 50% by weight of at least one other vinyl monomer copolymerizable with the vinyl monomer, and the reduced viscosity of the polymer (polymer 0.IJ'
Dissolved in 100 dK of tetraroform and measured at 25°C) is 0
, more than 1 l/g of thermoplastic polymer.

[1 [) Rubber-containing polymer acrylic acid alkyl ester 50 to 99.9% by weight, other copolymerizable vinyl monomers 0 to 40% by weight, and copolymerizable cross-a-monomer 0.1 In the presence of 100 parts by weight of an elastic copolymer obtained by polymerizing a monomer mixture consisting of ~10% by weight, 50 to 100% by weight of a methacrylic acid ester and 0 to 100% by weight of a vinyl monomer copolymerizable therewith. A rubber-containing polymer obtained by polymerizing 10 to 1000 parts by weight of a monomer or a mixture thereof consisting of 50% by weight.

[l] Thermoplastic polymer methacrylic acid ester 1L having an alkyl group with a prime number of 1 to 4 150 to 100% by weight and at least one other vinyl monomer copolymerizable with the same O to 50% by weight The reduced viscosity of the polymer (measured at 25°C after dissolving 0.IP of the polymer in 100% of chloroform) is o, i 7/P
A thermoplastic polymer that is:

In the present invention, if the thermoplastic polymer [13] is less than 0.1 part by weight in the thermoplastic resin composition of the present invention, sufficient moldability cannot be obtained; If the amount exceeds 20 parts by weight, the viscosity of the resin composition becomes too high, and the moldability deteriorates, which is not preferable.

The thermoplastic polymer [I] in the present invention is composed of 50 to 100% by weight of methyl methacrylate and 0 to 50% by weight of other vinyl monomers copolymerizable with this, and the reduced viscosity of the resulting polymer ( It is a polymer obtained by dissolving polymer 0.1I in chlorotetraform at 100 dK and polymerizing it to a value of 0.1 to 2 (measured at 25°C), and it is a component that plays an important role in moldability. . The reduced viscosity of the thermoplastic polymer [1) is important, and if the reduced viscosity is 0.11 gP or less, the desired moldability cannot be obtained. A particularly preferable range of reduced viscosity is 0.2 to 1.21/P.

In the thermoplastic polymer [I] used in the present invention, a vinyl monomer copolymerizable with methyl methacrylate [
For example, acrylic acid alkyl esters, methacrylic acid alkyl esters, aromatic vinyl compounds, vinyl cyan compounds, etc. can be used.

The acrylic acid alkyl ester preferably has an alkyl group having 2 to 10 carbon atoms, such as ethyl acrylate, acrylic A/l! ! Examples include propyl, n-butyl acrylate, inbutyl acrylate, hexyl acrylate, octyl acrylate, and 2-ethylhexyl acrylate.

As the methacrylic acid alkyl ester, those in which the alkyl group has 2 to 4 carbon atoms can be used, such as ethyl methacrylate, propyl methacrylate, isopropyl methacrylate,
Examples include n-butyl methacrylate, isobutyl methacrylate, and tert-butyl methacrylate.

Examples of aromatic vinyl compounds include styrene, α-substituted styrene, nuclear-substituted styrene, and derivatives thereof, such as α
-Methylstyrene, chlorostyrene, vinyltoluene, etc.

Furthermore, examples of the vinyl cyanide compound include acrylonitrile, methacrylonitrile, and the like.

As the polymerization initiator, ordinary inorganic initiators such as persulfates, organic peroxides, azo compounds, etc. are used alone, or
Alternatively, a combination of the above compound and a sulfite, hydrogen sulfite, thiosulfate, first metal salt, sodium formaldehyde sulfoxylate, etc. can be used as a redox initiator. Preferred persulfates as initiators include sodium persulfate, potassium persulfate, ammonium persulfate, etc., and organic peroxides include t-butyl hydroperoxide, cumene hydroperoxide, benzoyl peroxide, lauroyl peroxide, etc. be.

The molecular weight and molecular weight distribution of the copolymer are important factors for the effect of imparting processability, and an appropriate chain transfer agent can be used depending on the purpose.

Polymerization can be carried out under normal emulsion polymerization conditions at a temperature higher than the decomposition temperature of the initiator, and polymerization can be carried out in one stage or in multiple stages depending on the purpose.

The copolymer can usually be recovered in powder form by salting out or acid precipitation, followed by ν water flow, or by spray drying or freeze drying.

The rubber-containing polymer (It) in the present invention is a graft copolymer having a multilayer structure containing an acrylic acid alkyl ester as the main component of the rubber and having an effect of imparting excellent impact resistance and elongation to the resin composition. It is a combination.

The rubber-containing polymer [II] in the present invention includes 50 to 99.9% by weight of an acrylic acid alkyl ester, 0 to 50% by weight of other copolymerizable vinyl monomers, and 0% of copolymerizable crosslinking monomers. A monomer or a monomer mixture consisting of 1 to 10% by weight is (co)polymerized in at least one stage to obtain an elastic body, and then 50 to 100 parts by weight of methacrylic acid ester is added in the presence of 100 parts by weight of the elastic body. % and 0 to 50 weight % of another vinyl monomer copolymerizable with this monomer or a monomer mixture of 10 to 1000 parts by weight in at least one stage.

If the acrylic acid alkyl ester in the elastic body is less than 50% by weight, the effect of improving impact resistance will be small, which is not preferable. If the crosslinkable monomer in the elastic body is less than 0.1% by weight, a sufficient crosslinking effect cannot be obtained, and if it exceeds 10% by weight, the crosslinking will be too strong and the elastic properties of the elastic body will be impaired. This is not preferable because impact resistance decreases.

As the acrylic acid alkyl ester that can be used here,
Acrylic acid alkyl esters in which the alkyl group has 1 to 8 carbon atoms, such as butyl acrylate, acrylic acid-
2-ethylhexyl and the like are particularly preferred. In obtaining the elastic copolymer, less than 50% by weight of other copolymerizable vinyl monomers can be copolymerized. Other copolymerizable vinyl monomers used here include methacrylic acid alkyl esters such as methyl methacrylate, butyl methacrylate, and cyclohexyl methacrylate, styrene, acrylonitrile, and the like. When polymerizing a monomer or monomer mixture containing an acrylic acid alkyl ester as a main component, it is necessary to crosslink this (co)polymer. The crosslinking monomer used is not particularly limited, but preferably ethylene glycol dimethacrylate, ethylene glycol diacrylate, 1,3-butylene dimethacrylate, 1,4-butanediol diacrylate,
Examples include allyl acrylate, allyl methacrylate, diallyl heptatalate, triallyl cyanurate, triallyl isocyanurate, divinylbenzene, allyl turbate, diallyl maleate, trimethylolpropane triacrylate, allyl cinnamate, etc. They can be used alone or in combination.

As the monomer to be grafted, a monomer or a monomer mixture containing methacrylic acid ester as the main component is used in an amount of 10 parts by weight to 100 parts by weight of the elastic body containing acrylic acid ester as the main component.
1000 parts by weight can be polymerized in at least one stage, and the preferred range is 20 parts by weight to 200 parts by weight.

If the amount to be grafted is less than 10 parts by weight, it is difficult to recover the rubber-containing polymer as a good powder, and if the amount to be grafted exceeds 500 parts by weight, the desired impact resistance cannot be obtained. Both are unfavorable.

The proportion of rubber-containing polymer CID is the same as that of thermoplastic resin [13,
The amount is 5 to 99.9 parts by weight based on the total of 100 parts by weight of [I]. If the proportion of the rubber-containing polymer (n) is less than 5 parts by weight, impact resistance and film elongation will decrease.

Monomers that can be copolymerized with methacrylic acid ester include:
Methacrylic acid alkyl esters such as ethyl methacrylate, butyl methacrylate, and 2-ethylhexyl methacrylate; acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate; styrene; its derivatives,
Examples include acrylonitrile, methacrylic acid, acrylic acid, itaconic acid, maleic acid, fumaric acid, vinyltoluene, etc., and preferably acrylic acid alkyl esters such as methyl acrylate and ethyl acrylate.

The rubber-containing polymer [II] in the present invention is preferably obtained by an emulsion polymerization method, and the same catalysts, emulsifiers, and chain shearing agents used to obtain the thermoplastic polymer [I] are used. It can also be recovered in powder form like the thermoplastic polymer [I].

In the present invention, the thermoplastic polymer [I] has 1 to 4 carbon atoms.
It is a polymer obtained by polymerizing a monomer containing at least 50% by weight of a methacrylic ester having an alkyl group, and methyl methacrylate is most preferred. If the methacrylic acid ester content is 50% by weight or less, the moldability during film/sheet molding will be poor, and the transparency of the resulting film will also deteriorate.

Further, if the reduced viscosity exceeds 0.11 gP, fluidity deteriorates, which is not preferable. The method of polymerizing the thermoplastic polymer [11] is not particularly limited, and various commonly known methods such as suspension polymerization and emulsion polymerization are applicable.

The present invention provides the thus obtained thermoplastic polymer CI],
It is a resin composition consisting of [l) and a rubber-containing polymer [11], and is a resin composition that has extremely excellent moldability without impairing the original properties of methacrylic resin.

The thermoplastic resin composition of the present invention comprises a thermoplastic polymer [I]
, [I] and the rubber-containing polymer [111] are melt-kneaded. Prior to melt mixing, the prescribed amounts of each are thoroughly and uniformly mixed with stabilizers, lubricants, dyes, pigments, fillers, etc. as necessary using a powder mixer such as a V-type blender or Henschel mixer. After that, the mixture is melt-kneaded at 160 to 280''C using a Banbury mixer, a bluff gelaf, a mixing roll, a screw type extruder, or the like.

By molding the thus obtained composition of the present invention using an injection molding machine or an extrusion molding machine, transparency, surface gloss,
A molded product with excellent impact resistance can be obtained.

Furthermore, the composition of the present invention can be made into a film-like molded product having excellent transparency, weather resistance, and surface gloss by employing a melt extrusion method such as a T-die method, an inflation method, or a calendar method. . The preferred temperature for carrying out melt extrusion is 180 to 260°C.

The film-like molded product obtained from the composition of the present invention can improve its weather resistance and decorative effect by adhering or laminating it to steel plates, plastic sheets, wood, etc. by taking advantage of its excellent physical properties. .

The present invention will be explained in more detail with reference to Examples below. In the examples, parts represent parts by weight, and % represents weight %.

The total light transmittance, tear strength, impact strength, and film formability in the following examples were determined by the following methods.

Total light transmittance: Measured using an integral haze meter in accordance with Human STM D1003-61.

Tear strength: determined according to JZS P-8116K using the Elmendorf method with a cut of 2n.

Impact strength: A DuPont falling weight test was conducted to determine the 50% fracture height.

Film formability: The thickness at 10 points in the width direction of the film was measured, and the thinnest thickness that could be formed without thickness unevenness exceeding 20% of the average value was determined.

[Examples 1 to 5, Comparative Examples 1 to 3] &) Production of thermoplastic resin C1l 200 parts of ion-exchanged water substituted with nitrogen was charged into a reaction vessel, and 1 part of potassium oleate and 0.3 part of potassium persulfate were added as emulsifiers. I prepared it. Subsequently, 40 parts of methyl methacrylate, 10 parts of n-butyl acrylate, n-octyl mercaptan o, oo
5 m of the solution was charged, and the polymerization was completed by stirring at 65° C. for 3 hours under a nitrogen atmosphere. Subsequently, 2 parts of a monomer mixture consisting of 48 parts of methyl methacrylate and 2 parts of n-butyl acrylate were added.
The mixture was dropped over a period of time and held for 2 hours after completion of the dropwise addition to complete polymerization. The obtained latex was added to a 0.25% sulfuric acid aqueous solution, and the polymer was separated out, dehydrated, washed with water, and dried to recover the polymer in powder form. Reduced viscosity η of the obtained copolymer
sp/( was 0.381/P.

b) Production of rubber-containing polymer (II) Raw materials in the following proportions were charged into a reaction vessel, and polymerization was completed while stirring at 50° C. for 4 hours in a nitrogen atmosphere to obtain an elastic latex.

Butyl acrylate (BA) 77
parts Styrene 22.7 parts Allyl methacrylate 0.3 parts Sodium dioctyl sulfosuccinate 2.0 parts Deionized water 300 parts Potassium persulfate 0.3 parts Disodium phosphate dihydrate 0.5 parts Sodium hydrogen phosphate 2 0.3 parts of aqueous salt 100 parts by weight (as solid content) of this elastic latex was placed in a reaction vessel, and the air was sufficiently purged with nitrogen while stirring, and the temperature was raised to 80°C.
After adding an aqueous solution consisting of 0.125 parts and 2 parts of water, a mixture consisting of 60 parts of methyl methacrylate, 0.05 parts of n-octyl mercaptan, and 0.125 parts of t-butyl hydroperoxide was added while keeping the temperature at 80°C. was added dropwise over 2 hours and then maintained for 2 hours to complete polymerization.

The obtained copolymer latex was added to a 3% saline solution, followed by salting out, dehydration, washing with water, and washing to obtain a rubber-containing polymer [1] in powder form.

C) Production of molded articles The thermoplastic polymer (11) obtained as described above and the rubber-containing polymer (nl) and the thermoplastic polymer [I] methyl methacrylate/methyl acrylate copolymer [methacrylic acid Methyl/methyl acrylate = 98/2, ηsp/c
= 0,061/P:) were mixed in a Henschel mixer at various ratios shown in Table 1. Next, the mixture was melt-kneaded and pelletized using a 40wφ screw extruder (L10=26) at a cylinder temperature of 200 to 260°C and a die temperature of 250°C.

The obtained pellets were dried at 80° C. for a day and night, and then formed into a film using a T-die.

Table 1 shows the physical properties and moldability of the obtained film. still,
The physical properties of the films were all measured for films with a thickness of 0.10. From Table 1, it can be seen that by mixing a specific amount of thermoplastic polymer CII, the thin film formability is significantly improved.

[Examples 6 to 8, Comparative Example 4] 1) Production of thermoplastic polymer [I] 200 parts of ion-exchanged water purged with nitrogen was charged into a reaction vessel, and 1.5 parts of potassium oleate and 0 potassium persulfate were added as emulsifiers.
．． I have prepared 3 parts. Subsequently, 80 parts of methyl methacrylate,
20 parts of ethyl acrylate, n-octyl mercaptan
, oos parts were charged, and the mixture was stirred at 65° C. for 3 hours under a nitrogen atmosphere to complete the polymerization (Example 6). Examples 7 and 8 and Comparative Example 4 are shown in which the amount of n-octyl mercaptan was similarly changed.

Films were obtained in the same manner as in Example 1 using the same rubber-containing polymer (U) and thermoplastic polymer [I] as in Example 1, and the above various thermoplastic polymers [I]. Table 2 shows the physical properties and film formability of the obtained film. From Table 2, thermoplastic polymer [
It can be seen that when the reduced viscosity of No. 11 was 0.11 gP, the film formability deteriorated.

[Examples 9 to 12, Comparative Example 5] 1) Production of rubber-containing polymer (n) An elastic latex containing acrylic ester as a main component was obtained in the same manner as in Example 1-b).

When graft polymerizing a monomer mixture consisting of 85% methyl methacrylate, 14% styrene, and 1% acrylic a:1fN to this elastic latex, the amount to be grafted to 100 parts (as solid content) of the elastic latex was changed, Various rubber-containing polymers [II] were obtained. Table 3 shows the physical properties and moldability of the film obtained by operating the above rubber-containing polymer Cl) and the same thermoplastic polymer [l] and/or [I] as in Example 1 in the same manner as in Example 1. Shown below. It can be seen that when the amount of grafting is less than 10 parts, a good powder cannot be obtained, and when the amount of grafting exceeds 500 parts, the impact resistance and elongation of the film are reduced.

〔Effect of the invention〕

As detailed above, the present invention makes it possible to provide a resin composition that has excellent moldability without impairing the original excellent properties of methacrylic resin.

Claims (1)

[Claims] 1) Thermoplastic polymer [I] shown below: 0.1 to 2
0 parts by weight, rubber-containing polymer [II] 5 to 99.9 parts by weight,
Thermoplastic polymer [III] consists of 0 to 94.9 parts by weight,
A thermoplastic resin composition in which the total of [I], [II], and [III] is 100 parts by weight. [I] A thermoplastic polymer consisting of 50 to 100% by weight of methyl methacrylate and 0 to 50% by weight of at least one other vinyl monomer that can be copolymerized with it, and the reduced viscosity of the polymer (polymer A thermoplastic polymer with a content of more than 0.1 l/g (measured at 25°C when 0.1 g is dissolved in 100 ml of chloroform). [II] Rubber-containing polymer acrylic acid alkyl ester 50-99.9% by weight, other copolymerizable vinyl monomers 0-40% by weight, and copolymerizable crosslinking monomers 0.1-10% by weight 50 to 100 parts by weight of a methacrylic acid ester and 0 to 50 parts by weight of a vinyl monomer copolymerizable therewith in the presence of 100 parts by weight of an elastic copolymer obtained by polymerizing a monomer mixture consisting of A rubber-containing polymer obtained by polymerizing 10 to 1000 parts by weight of a monomer or a mixture thereof. [III] Thermoplastic polymer 50 to 100% by weight of a methacrylic ester having an alkyl group having 1 to 4 carbon atoms, and 0 to 50% by weight of at least one other vinyl monomer copolymerizable with this The reduced viscosity of the polymer (0.1 g of polymer is mixed with chloroform 10
A thermoplastic polymer having a solubility of 0.1 l/g or less (measured at 25°C) dissolved in 0 ml.