JPH0463853A - Thermoplastic resin molding - Google Patents

Abstract

PURPOSE:To obtain a thermoplastic resin molding improved in fluorocarbon resistance, chemical resistance, dimensional stability, impact resistance and rigidity by mixing a styrene resin with a fibrous or reticular polyolefin resin and a styrene block copolymer elastomer. CONSTITUTION:100 pts.wt. total of 50-95wt.% styrene resin (e.g. styrene/ acrylonitrile copolymer) and 50-5wt.% polyolefin resin (e.g. PE) having a viscosity equal to or higher than the viscosity of component A and being in the form of a fiber having an aspect ratio of 50/1, a thickness of a single fiber of 0.1-100mum or in the form of a reticulum of a thickness of a single fiber of 0.1-200mum is mixed with 1-25 pts.wt. styrene block copolymer elastomer, e.g. hydrogenated styrene/butadiene/styrene block copolymer.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention improves resistance to fluorocarbon gas, other organic gases, and organic solvents by forming a special structure, and also has excellent mechanical strength and dimensional stability. The present invention also relates to a thermoplastic resin molded product made of a styrene resin and a polyolefin resin.

[Prior art] Styrenic resins such as rubber-modified polystyrene resin (HIPS resin) and acrylonitrile-butadiene-styrene copolymer resin (ABS resin) have high rigidity, dimensional stability,
Because it has excellent moldability, it has been widely used in general household goods, home appliances, office equipment, etc. On the other hand, these styrenic resins have chemical resistance, especially in recent years due to regulations on the use of fluorocarbon gases, such as Freon R-123 (C) ICI□CF3), which does not destroy the ozone layer, and Freon R-14l b ( C) It has poor resistance to I3CC12F), and when it comes into contact with these, the surface is attacked, causing whitening, crazing, and cracking. For this reason, for example, when styrene-based resin is used in general home appliances such as electric refrigerators, it comes into contact with polyurethane insulation materials that use fluorocarbon gas as a foaming material, resulting in the above-mentioned problems of whitening, crazing, and cracking. has been limited.

In addition, polyolefin resins such as polypropylene (PP) resins have excellent chemical resistance, especially Freon R123 and R-1.
41b gas will not cause any appearance defects, but on the other hand,
There are problems such as poor moldability and rigidity.

Therefore, an attempt was made to obtain a resin by melt-kneading a styrene resin and a polyolefin resin, but the compatibility was poor, mechanical strength decreased, and delamination occurred, making it impractical for practical use. In addition, methods for improving the compatibility of this resin composition have been studied; for example, methods of adding styrene-butadiene block copolymer elastomer or styrene-propylene rubber to styrene graft are known. It was not completely satisfying. Furthermore, in order to improve chemical resistance, it is necessary to knead a considerable amount of polyolefin resin, which poses the problem of impairing dimensional stability and rigidity, which are characteristics of styrene resins.

[Problems to be Solved by the Invention] The purpose of the present invention is to provide styrene resins and polyolefin resins that have improved resistance to fluorocarbon gas, other organic gases, and organic solvents, and also have excellent mechanical strength, dimensional stability, and rigidity. An object of the present invention is to provide a thermoplastic resin molded product having a special structure consisting of:

[Means for Solving the Problems] As a result of intensive studies in order to solve the above-mentioned problems, the present inventors have found that the above-mentioned resistance and mechanical properties can be achieved by making the mixed form of styrene resin and polyolefin resin into a special structure. The present invention was achieved by discovering that the mechanical strength can be significantly improved.

That is, the present invention includes (a) 50 to 95% by weight of a styrene resin, (b) 50 to 5% by weight of a polyolefin resin, and (C) a styrene block based on a total of 100 parts by weight of (a) + (b). This is a thermoplastic resin molded article, which is a resin composition containing 01 to 25 parts by weight of a polymer elastomer, and is characterized in that the polyolefin resin component has a fibrous or network structure.

The styrene resin component (a) constituting the thermoplastic resin molded article of the present invention includes, for example, styrene monomer, a-substituted styrene such as methylstyrene, pt-butylstyrene, p-methylstyrene, vinyltoluene, Single or copolymers of styrene derivative monomers such as nuclear-substituted styrene such as chlorostyrene; copolymers of one or more styrenic monomers with other polymers that can be copolymerized;
For example, styrene-acrylonitrile copolymer (ΔS resin), a graft polymer obtained by graft polymerizing polybutadiene rubber with one or more styrene monomers or other monomers, such as styrene graft polymer (HIPS). resin), styrene-acrylonitrile-butadiene graft polymer (ABS resin), and the like. These are manufactured by methods well known to those skilled in the art and are commercially available.

Examples of the polyolefin resin of component (b) include polyethylene, polypropylene, propylene-ethylene copolymer, polybutene, and polymethylpentene. These are manufactured by methods well known to those skilled in the art and are commercially available.

The styrenic block copolymer elastomer as component (C) used in the present invention is a polymer block of aromatic vinyl hydrocarbon such as styrene, and a conjugated diene polymer typified by 1,3-butazinine and isoprene. It is a block copolymer consisting of blocks, and diblock, triblock or more are used. These block copolymer elastomers are commercially available; for example, hydrogenated styrene/butadiene/styrene block copolymers are available under the trade name Kraton from Shell Chemical.

In order for the thermoplastic resin molded product to solve the above problems and maintain rigidity, chemical resistance, and dimensional stability at the same time, the dispersion form of the polyolefin resin, which is a minor component, in the composition must be in a fibrous or network structure. must be retained. This is done by uniformly mixing (a) styrene resin, (b) polyolefin resin, and (c) styrene block copolymer elastomer using a high-speed stirrer such as a tumbler or Henschel mixer, and then using an extruder or the like. When a composition in the form of a pellet, sheet, or injection molded product obtained by melt-kneading is immersed in an organic solvent such as methyl ethyl ketone or chloroform for a sufficient period of time to dissolve the solvent-soluble components, the insoluble components are recovered. The dissolved residue of the polyolefin component can be easily confirmed by observing it with a scanning electron microscope.

In other words, in the microscopic image of the above-mentioned dissolution residue, a dispersion polyolefin resin with a long axis/short axis ratio of 50/1 or more is said to be fibrous, and the fibrous polyolefin resins are intertwined with each other and are not in contact or in contact with each other. The state in which they are fused together to form a network is called a network structure.

In addition to the above-mentioned microscopic image confirmation, whether the thermoplastic resin composition has a fibrous or network structure or not can be confirmed by confirming that the resistance to fluorocarbon gas, other organic gases, and organic solvents is significantly different. It is also possible to determine the distribution form. These confirmations are extremely important in determining whether the thermoplastic molded product of the present invention is new. This is because this is a phenomenon that has not been observed in conventional molded products.

In the above explanation, the thickness of the single fiber forming the fibrous structure is usually in the range of 01 to 100 μm, preferably 0.
It is in the range of 1 to IOμs. On the other hand, the thickness of the fibrous material forming the network structure cannot be absolutely defined as can be seen from FIG. 1, but it is usually in the range of 01 to 200 μm, preferably in the range of 01 to 50 μm, These ranges are (
It also changes depending on the blending ratio of a) styrene resin and (b) polyolefin resin.

In the thermoplastic resin composition of the present invention, the blending ratio of (a) styrene resin and (b) polyolefin resin is (a)
is in the range of 50 to 95% by weight, and (b) is in the range of 50 to 5% by weight. If (a) is less than 50% by weight, the dimensional stability and rigidity are poor, and if it exceeds 95% by weight, the boron olefin component may take on a fibrous or network structure, and chemical resistance is not improved. The blending ratio of the styrene block copolymer elastomer (c) is in the range of 0.1 to 25 parts by weight based on 100 parts by weight of (a)+(b). If (C) is less than 01 parts by weight, the compatibility between (a) styrene resin and (b) polyolefin resin will be reduced, resulting in poor mechanical strength, and if it exceeds 25 parts by weight, chemical resistance and rigidity will be reduced. Undesirable.

The method for manufacturing the thermoplastic resin molded product of the present invention involves using commonly known methods such as injection molding and extrusion molding after uniform mixing using the aforementioned high-speed stirrer and melt mixing. a) Component styrenic resin and (
It is necessary to pay attention to the viscosity ratio with the polyolefin resin of component b). That is, the viscosity of the polyolefin resin as a dispersion system must be equal to or higher than the viscosity of the styrene resin as the matrix component. Although it is difficult to define the viscosity ratio unconditionally, for example, at a certain temperature,
This can be understood as a viscosity ratio under shear such that 20>+b+8, to ≧1, preferably 10:1. The viscosity in this case can be measured, for example, at 210° C. using a flow tester (for example, Shimadzu Corporation's product name CF300).

If the viscosity of the polyolefin resin is low, the component will not have a fibrous or network structure, and there will be no effect of improving resistance to fluorocarbon gas, other organic gases, or organic solvents, which is not preferable. (The same viscosity ratio as above is, for example, 1>tb+8a>
It is shown as 0.1. ) In this case, the amount of crystal nucleating agent effective for the polyolefin component is 0% for the polyolefin resin.
By adding up to 0.01% by weight or less, the crosstalk property of the composition is improved and the composition takes on a fibrous or network structure, thereby improving the resistance to fluorocarbon gas, other organic gases, and organic solvents. There are no particular restrictions on the crystal nucleating materials, which are generally used.
Examples include polyvinylcyclohexane as disclosed in No. 1.

In addition, the thermoplastic resin molded article of the present invention may contain various additives used in ordinary thermoplastic resins, such as colorants, lubricants, plasticizers, antioxidants, stabilizers, antistatic agents,
It is also possible to add ultraviolet absorbers and the like.

[Example] The present invention will be explained in more detail with reference to Examples below.

However, the present invention is not limited to these examples.

Note that evaluations of fluorocarbon resistance, chemical resistance, and physical properties described in Examples and Comparative Examples were performed according to the following methods.

(1) Freon resistance evaluation, chemical resistance evaluation The critical strain for Freon 123, Freon 141b, salad oil, and MCT oil and fat was measured.

x2/l 22+y"/4.52=15 made by injection molding using the ellipse expressed by the formula 1 on a 1/4 ellipse jig
A 0x50mm, 1mm thick flat plate was fixed, CFC was applied in a gas atmosphere, and the others were applied, and after being left at 23℃ for 24 hours, the test piece was observed and the minimum strain (critical strain) that caused cracks was determined. , evaluated using the symbols shown below.

○ No appearance defects or critical strain of 0.3 or more Δ: Critical strain of 0.15 or more and less than 0.03 x - Critical strain of less than 0.15 or whitening, swelling, dissolution, or other appearance defects.

(2) Izotsu impact strength Compliant with JIS K-7207.

(3) Bending strength, bending modulus Compliant with JIS K-7203.

Reference example 1 (a) As a styrene resin, 210'CI 0se
GP polystyrene having a melt viscosity of 2.5XlO' poise at a shear rate of c-' [manufactured by Mitsui Toatsu Chemical ■, trade name Toplex 1F 5% by weight, (b) as a polyolefin resin at 210°C 10 sec-' shearing Polypropylene having a melt viscosity of 4.5 x 10' poise at speed [manufactured by Mitsui Toatsu Chemical ■, trade name Noblen 125% by weight,
(a) + (b) C) Styrene-based block copolymer elastomer based on 100 parts by weight in total
Hydrogenated butadiene-styrene copolymer [manufactured by Shell Chemical ■,
110 parts by weight of Kraton (trade name) was mixed using a tumbler, and the mixture was heated to 220°C using a single-screw extruder to a thickness of 0.4 mm.
A sheet was created. When this sheet was immersed in methyl ethyl ketone overnight and observed under an electron microscope, a network structure as shown in FIG. 1 was confirmed.

Reference Example 2 In Reference Example 1, the polyolefin resin was heated at 210°C.
Melt viscosity at 10 sec-' shear rate is 2.5X
The same procedure as Reference Example 1 was carried out except that polypropylene having a 10' poise was used, but a fibrous dispersion form as shown in FIG. 2 was confirmed.

Reference Example 3 In Reference Example 1, 210° as a polyolefin resin
Melt viscosity at shear rate of C105ec-' 5X
The same procedure as in Reference Example 1 was carried out except that polypropylene having 10' poise was used, but as shown in FIG. 3, no fibrous or network structure was observed.

Example 1 As in Reference Example 1, (a) 21 as the styrene resin.
GP polystyrene having a melt viscosity of 2.5 x 10' poise at a shear rate of 0'C10sec-' [manufactured by Mitsui Toatsu Chemicals, trade name: Toplex 1F 5% by weight, (b
) Polypropylene having a melt viscosity of 4.5 x 10' poise at a shear rate of 210°C and 10 sec-' as a polyolefin resin [manufactured by Mitsui Toatsu Chemicals, trade name Noblen 125% by weight, (a) + (b) total 100 parts by weight c) Styrenic block copolymer As an elastomer, 10 parts by weight of a styrene-hydrogenated butadiene-styrene copolymer [manufactured by Shell Chemical ■, trade name: Kraton] was mixed using a tumbler, and mixed using a single-screw extruder. It was extruded into pellets at 220°C. This pellet was immersed in methyl ethyl ketone for a day and night, and when it was observed under an electron microscope, a network structure was confirmed. An injection molded test piece was prepared from this pellet, and the above items were evaluated. The results are shown in Table 1.

All of them are excellent in fluorocarbon resistance, chemical resistance, impact resistance, and rigidity, and have sufficient practical value.

Examples 2 to 5 In Example 1, the styrene resin (a), the polyolefin resin (b), and the styrene block copolymer elastomer (C) were blended in the proportions shown in Table 1, and pellets were prepared. The same procedure as in Example 1 was carried out except that . The results are shown in Table 1, and the dispersion form of network structure was confirmed in all cases, and they were excellent in fluorocarbon resistance, chemical resistance, impact resistance, and rigidity, and had sufficient practical value.

Example 6 In Example 1, the polyolefin resin (b) had a melt viscosity of 2 at a shear rate of 210°C 10 sec-'.
．． The same procedure as in Example 1 was carried out, except that 125% by weight of polypropylene having 5 x lO' poise (manufactured by Mitsui Toatsu Chemical Co., Ltd., trade name: Noblen) was blended. The results are shown in Table 1, and a fibrous dispersion form was confirmed, and the product had excellent fluorocarbon resistance, chemical resistance, impact resistance, and rigidity, and had sufficient practical value.

Example 7 In Example 1, 21 as the styrene resin of (a)
The melt viscosity at a shear rate of 0° C. 10 sec-' is 2.
Styrene graft polymer (HI
The same procedure as in Example 1 was carried out except that 75% by weight of PS resin (manufactured by Mitsui Toatsu Chemical Co., Ltd., trade name: TOBOLEX) was blended.

The results are also shown in Table 1, and the dispersion form of a network structure was confirmed, and it was found to have excellent fluorocarbon resistance, chemical resistance, impact resistance, and rigidity, and to have sufficient practical value.

Example 8 In Example 1, 21 as the styrene resin of (a)
The melt viscosity at a shear rate of 0°C 10 sec-' is 25
The procedure of Example 1 was repeated except that 75% by weight of a styrene-acrylonitrile graft polymer (ABS resin) having a size of 104 poise (manufactured by Japan Synthetic Rubber ■, trade name: ABSIO) was blended. The results are shown in Table 1, and the dispersion form of a network structure was confirmed, and it was found to have excellent fluorocarbon resistance, chemical resistance, impact resistance, and rigidity, and to have sufficient practical value.

Comparative Examples 1 to 2 In Example 1, (a) styrene resin, (b) polyolefin resin, and (c) styrene block copolymer elastomer were blended in the proportions shown in Table 2 and pelletized. Except for this, the same procedure as in Example 1 was carried out. Unlike the examples, no network structure was observed, and the fluorocarbon resistance and chemical resistance were poor.

Comparative Example 3 The procedure of Example 1 was repeated except that the styrene block copolymer elastomer (C) was not used and the mixture was pelletized. Although it had a fibrous dispersion form, it had poor impact resistance and could not be put to practical use.

Comparative Example 4 Example 1 except that (a) styrene resin, (b) polyolefin resin, and (C) styrenic block copolymer elastomer were blended in the proportions shown in Table 2 and pelletized. Same as 1. No network structure or fibrous dispersion form was observed, and the resistance to fluorocarbons and chemicals was poor, making it impossible to put it to practical use.

Comparative Example 5 In Example 1, as the polyolefin resin (b), polypropylene having a melt viscosity of 1.5 x 10' poise at a shear rate of 210'C10sec-' [manufactured by Mitsui Toatsu Chemicals, trade name No. 112325% by weight] was used. The procedure was the same as in Example 1 except that the ingredients were blended.

The results are shown in Table 1. Since no measures were taken to create a network structure or fibrous dispersion, the pellets were immersed in methyl ethyl ketone for a day and night, and then observed under an electron microscope. It has a dispersed form of islands, and has inferior fluorocarbon resistance and chemical resistance compared to Example 1.
It could not be put to practical use.

Example 9 Example 1 except that a styrene-isoprene copolymer manufactured by Kuraray ■, trade name Sebuton] was blended as the styrene block copolymer elastomer (C) in the proportions shown in Table 1. I did the same thing. The results are shown in Table 1, and the dispersion form of the network structure was confirmed, and the fluorocarbon resistance and
It had excellent chemical resistance, impact resistance, and rigidity, and had sufficient practical value.

Example 10 Same as Comparative Example 5 except that 0.01 parts of polyvinylcyclohexane was blended into pellets based on 100 parts by weight of polyolefin resin as a crystal nucleating material effective for the polyolefin component. did. Results first
As shown in the table, the dispersion form of a network structure was confirmed, and it was found to have excellent fluorocarbon resistance, chemical resistance, impact resistance, and rigidity, and to have sufficient practical value.

[Effects of the invention] The thermoplastic resin molded product of the present invention has excellent resistance to fluorocarbons and chemicals, as well as impact resistance and rigidity, and is suitable for use in general home appliances, various industrial parts, general household goods, etc. It is suitably used for.

[Brief explanation of drawings]

FIG. 1 is an example of a scanning electron micrograph showing the shape of fibers in a thermoplastic resin molded product having a network structure according to the present invention, and FIG. FIG. 3 is an example of a similar photograph showing the shape of a conventional thermoplastic resin molded product. Patent applicant Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] 1, (a) 50-95% by weight of styrene resin, (b) 50-5% by weight of polyolefin resin, and (a) + (b)
A resin composition comprising 0.1 to 25 parts by weight of (c) styrenic block copolymer elastomer to 100 parts by weight in total, wherein the polyolefin resin component has a fibrous or network structure. Characteristic thermoplastic resin molded products.