JPS61252259A - Resin composition - Google Patents

Abstract

PURPOSE:To improve thermal stability during processing as well as tranparency and impact resistance, by combining a conjugated diolefin/arom. vinyl hydrocarbon block copolymer having an MW within a specified range and contg. a specified amount of a component having a relatively high MW with a styrene polymer. CONSTITUTION:The title compsn. is composed of 5-35wt% conjugated diolefin/ arom. vinyl hydrocarbon block copolymer (I) wherein main component has an MW of 40,000-120,000, the content of the arom. vinyl hydrocarbon is 10-60wt% and the content of component having an MW of 140,000 or above is 5-35wt% and 95-65wt% rubber-unmodified styrene polymer (II). 2-30pts.wt. rubber-modified styrene polymer may be blended with 100pts.wt. of the combined amount of components (I) and (II) to improve further impact resistance.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a resin composition comprising a block copolymer of a vinyl aromatic hydrocarbon compound and a conjugated diolefin and a non-ZAM modified styrene/based polymer, or Regarding resin compositions further blended with BIM-modified styrene/based polymers, transparency,
It is characterized by excellent impact resistance and thermal stability during processing.

[Conventional technology]

Hitherto, folystyrene has been widely used in food packaging containers and the like because it has excellent transparency, surface gloss, and a beautiful appearance, as well as excellent rigidity and tensile strength, but it has the drawbacks of poor impact resistance and brittleness. Many methods are known to improve this drawback, such as adding a block copolymer consisting of conjugated diolefin/vinyl substituted aromatic compound to polystyrene. For example, Tokuko Sho 45-1938
No. 8 and Japanese Patent Publication No. 47-43118 describe the use of linear block copolymers and branched radial block copolymers as impact modifiers for monostyrene. Also, JP-A No. 47-435 and JP-A No. 4
No. 7-34808 describes a method of blending a block copolymer and an impact-resistant T-modified styrene polymer with polystyrene.

[Problem that the invention seeks to solve]

However, although these methods improve the impact resistance of polystyrene, they have the drawback of significantly lowering its transparency, and a more effective method of improvement has been desired.

Several attempts have been made to meet this demand. For example, JP-A-54-62251 and JP-A-5
Publication No. 3-250 describes a method of blending a block copolymer with a low styrene content and a block copolymer with a high styrene content with polystyrene, and a method of blending these with a rubber-modified styrenic polymer. has been done.

Although transparency is considerably improved by these methods compared to the above-mentioned methods, on the other hand, the impact resistance is reduced and when used as a molded article, problems such as easy breakage due to impact occur.

[Means and effects for solving the problems] The present invention provides a block copolymer having a molecular weight within a specific range and containing a specific amount of a relatively high molecular weight component in combination with a styrene polymer. The present inventors have discovered that a resin composition can be obtained that has excellent properties such as hardness, impact resistance, and thermal stability during processing, and has accomplished the present invention.

That is, the present invention provides the following conditions: (ii) The main component has a molecular weight of 40,000 to 120,000, the content of the vinyl aromatic hydrocarbon compound is 10 to 60% by weight, and the component with a molecular weight of 140,000 or more is 5 to 35% by weight. 5 to 35% by weight of a block copolymer of a conjugated diolefin and a vinyl aromatic hydrocarbon compound; The composition further contains a rubber-modified styrenic polymer as a component (iin).
The resin composition contains 2 to 30 parts by weight per part by weight.

The present invention will be explained in detail below.

The block copolymer of component (ii) used in the present invention is:
The block copolymer has a vinyl aromatic hydrocarbon compound content of 10 to 60% by weight, preferably 20 to 50% by weight. The content of vinyl aromatic hydrocarbon compound is 10 weight tons
If it is less than 60% by weight, the transparency and impact resistance will decrease, and if it exceeds 60% by weight, the impact resistance will decrease, which is not preferable.

As a method for producing the block copolymer of component (ii), conventionally known methods such as Japanese Patent Publication No. 36-19286,
Special Publication No. Sho 43-17979, Special Publication No. Sho 49-3695
The method disclosed in Publication No. 7 etc. can basically be adopted.

These are 7
It is a method of block copolymerizing a conjugated diolefin and a vinyl aromatic hydrocarbon compound using an ionic polymerization initiator,
General formula, (AB) II, A-(-B-A)IT,
B+A−B )+t (In the above formula, At1j is a polymer block mainly composed of a vinyl aromatic hydrocarbon compound, and B is a polymer block mainly composed of a conjugated diolefin. The boundaries do not necessarily need to be clearly distinguished.Also, n is an integer of 1 or more,
Generally it is an integer from 1 to 5. ), or a linear block copolymer represented by the general formula % (In the above formula, A and B are the same as above, and X is a residue of a coupling agent such as silicon tetrachloride or tin tetrachloride. or a residue of a polyfunctional organolithium compound (m and n are integers of 1 or more, generally Fi1 to 5). The block copolymer used in the present invention may be a mixture of various structures described above. The polymer block mainly composed of vinyl aromatic hydrocarbon compounds has a vinyl aromatic hydrocarbon compound content of 50%! t, preferably 70% by weight or more of polymer f lock, and a vinyl aromatic hydrocarbon compound homopolymer block or a vinyl aromatic hydrocarbon compound homopolymer portion, a vinyl aromatic hydrocarbon compound, and a conjugated diene. A specific example thereof is a polymer block composed of a copolymer portion of . In addition, a polymer block mainly composed of a conjugated diene is
The content of conjugated diene is 50% by weight or more, preferably 70% by weight.
It is a polymer block of iif1 or more and is a conjugated diene homopolymer! A specific example of the copolymer block member of rock, a vinyl aromatic hydrocarbon compound and a conjugated die/die is a polymer block consisting of a combination of these. If there is a vinyl aromatic hydrocarbon compound copolymerized with the conjugated diene in these polymer blocks, even if this vinyl aromatic hydrocarbon compound is uniformly distributed in the polymer chain, The greatest feature of the present invention is that the molecular weight of the main component is 40,000 to 120,000, preferably 60,000 to 110,000, and the molecular weight of the main component is 40,000 to 120,000, preferably 60,000 to 110,000. 5 to 35% by weight, preferably 7 to 25% by weight of block copolymer is used as component (ii). If the molecular weight of the main component of the block copolymer is less than 40,000, the impact resistance will decrease, and if it exceeds 130,000, the impact resistance and thermal stability during processing will be poor, which is not preferable. In addition, if the component having a molecular weight of 140,000 or more is less than 5 folds, the impact resistance will decrease, and if it exceeds 35 ffifs, the impact resistance and thermal stability during processing will be poor, which is not preferred. The molecular weight herein refers to a value determined by gelatin migration chromatography (APC) using a calibration curve prepared using standard polystyrene commercially available for GPC. In addition, the molecular weight of the product and the molecular weight of the main component peak that is off in the kernon-meation chromatogram are the values determined using the above calibration curve. As a method for obtaining a block copolymer in which the molecule i of the main component is 40,000 to 130,000 and the component having a molecular Ik of 140,000 or more is 5 to 35% by weight, a block copolymer with a molecular weight of 40,000 to 130,000 can be obtained. A method of blending a polymer and a block copolymer with a molecular weight of 140,000 or more within the range specified in the present invention, or a method of blending a block copolymer with a molecular weight of 4
Produce a block copolymer of 10,000 to 130,000 according to a conventional method,
Examples include a method in which the living polymer is coupled with a coupling agent having two or more functional groups, and the molecular weight and content of the coupled polymer are adjusted within the range specified by the present invention.

As a coupling agent for the latter method, compounds having an epoxy group, incyanate group, imino group, aldehyde group, ketone group, ester group, acid anhydride group, halogen group, etc. can be used. The proportion of components having a molecular weight of 140,000 or more can be confirmed by comparing the area of the portion corresponding to the component in the gel permeation chromatogram with the area of the entire polymer.

In the present invention, the vinyl aromatic hydrocarbon used in the production of the block copolymer of component (+1) is styrene/
, o-methylstyrene, p-methylstyrene, p-t
artbutylstyrene, 1,3-dimethylstyrene, α
-Methylstyrene, vinylnaphthalene, vinylanthracene, etc., with styrene being a particularly common one. These may be used not only as a single type but also as a mixture of two or more types.

Further, the conjugated diene is a diolefin having a pair of conjugated double bonds having 4 to 8 carbon atoms, for example,
l,3-butadiene, 2-methyl-1,3-citadiene (isoprene), 2,3-,)methyl-1,3-citadiene, 1,3-pentadiene, 1,3-hexadiene, etc. But especially as a common one! ,3
- Examples include butadiene and isoprene. These may be used not only as a single type but also as a mixture of two or more types.

Particularly preferred block copolymers in the present invention include a short-linked vinyl aromatic hydrocarbon compound moiety in which the number of vinyl aromatic hydrocarbon-hydrogen compound units ranges from 1 to 5 in the block copolymer chain; Moreover, the content of the short chain vinyl aromatic hydrocarbon compound is 3 to 35 units, preferably 5 to 2 units.
It is a block copolymer of 5. Such a block copolymer t'i is particularly effective in improving impact resistance and is therefore effective in achieving the objects of the present invention.

In the present invention, the short-fed vinyl aromatic hydrocarbon compound portion in which the number of vinyl aromatic hydrocarbon compound units in the block copolymer chain ranges from 1 to 5 refers to the ozonolysis (Japan Rubber Association Journal) of the block copolymer. , 54(9)564 (ii
981)) of the components obtained by GPC (absorption wavelength 2
Using an ultraviolet absorption photometer detector set at 54 nm), the molecular weight corresponding to each count number was determined from a calibration curve created using standard polystyrene and polystyrene oligomer, and from the component corresponding to styrene monomer. This refers to the portion up to the component corresponding to the methylef pentamer (hereinafter referred to as the short-fed vinyl aromatic hydrocarbon compound portion).

The content of the short-term vinyl aromatic hydrocarbon compound portion is the content of the short-term vinyl aromatic hydrocarbon compound moiety relative to the total peak area in the gel permeation chromatogram of the component obtained by ozonolysis of the block copolymer. Refers to the area ratio of the hydrogen compound part.

The non-rubber-modified styrenic polymer used in the present invention as component (ii) is obtained by polymerizing the above-mentioned vinyl aromatic hydrocarbon compound or a monomer copolymerizable therewith. Monomers copolymerizable with vinyl aromatic hydrocarbon compounds include α-methylstyrene, acrylonitrile, acrylic esters, methacrylic esters,
Examples include maleic anhydride.

Particularly preferred non-rubber modified styrenic polymers include (c) folystyrene, styrene-α-methylstyrene copolymer;
Examples include acrylonitrile-styrene copolymer, styrene-methacrylic acid ester copolymer, and styrene-maleic anhydride copolymer, and these can be used alone or in a mixture of two or more.

In the present invention, the blending weight ratio of component (ii) and component (历) is such that component (ii) is 5 to 35% by weight, preferably 8 to 2% by weight.
It is 5% by weight. If the amount of the component is less than 5% by weight, the impact resistance improvement effect will not be sufficient, and if it exceeds 35% by weight, the transparency and rigidity of the composition will decrease, which is not preferable.

In the present invention, impact resistance can be further improved by blending a TM-modified styrenic polymer.

The TM-modified styrenic polymer that can be used in the present invention is obtained by polymerizing a vinyl aromatic hydrocarbon compound or a monomer copolymerizable therewith with an elastomer mixture, and the polymerization method includes suspension polymerization, emulsion polymerization,
Bulk polymerization, bulk-suspension polymerization, etc. are generally carried out. Seven polymers that can be copolymerized with vinyl aromatic hydrocarbon compounds
Examples include α-methylstyrene, acrylonitrile, acrylic ester, -methacrylic ester, maleic anhydride, and the like. Also, as an elastomer,
Natural bim, synthetic isoprenzam, butadienzam, styrene-butadienzam, high styrene rubber, polybutadienzam, chloropre/rubber, polybutene-2m, rubbery ethylene-propylene copolymer, rubbery butadiene-acrylonitrile copolymer, butyl rubber, Various nitrile rubbers, rubbery ethylene-vinyl acetate copolymers, rubbery ethylene-acrylic acid ester copolymers, rubbery atactic polypropylene resins, rubbery ethylene-acrylic acid ionomers, and the like are used.

These elastomers are generally dissolved in 2 to 70 parts by weight, and generally 3 to 50 parts by weight, per 100 parts by weight of the vinyl aromatic hydrocarbon compound or a monomer copolymerizable therewith. Alternatively, it can be subjected to bulk polymerization, bulk-suspension polymerization, emulsion polymerization, etc. in the form of latex.

Particularly preferred rubber-modified styrenic polymers include impact-resistant ZAM-modified styrene polymers, acrylonitrile-butadiene-styrene copolymers, acrylic ester-butadiene-styrene copolymers, and methacrylic ester-butadiene-styrene copolymers. Examples include impact-resistant rubber-modified styrene-maleic anhydride copolymer, and these can be used alone or as a mixture of two or more.

The blending amount of the Zam-modified styrenic polymer component (Ill) is:
Sum of component (ii) and component (ii)! The amount is 2 to 30 parts by weight, preferably 5 to 20 parts by weight, per 100 parts by weight.

When the blending amount of component (iii) is less than 2 parts by weight, the effect of improving impact resistance by blending component (iii) is small;
If it exceeds 30 parts by weight, transparency will deteriorate, which is preferable.0 The resin composition of the present invention can contain arbitrary additives, if necessary. The type of additive is not particularly limited as long as it is commonly used in plastic formulations, but examples include glass fiber, glass beads, inorganic reinforcing agents such as silica, charcoal, and talc, organic fibers, coumaron indene resin, etc. organic reinforcing agents, crosslinking agents such as organic peroxide and inorganic peroxide, titanium white, casen black,
Examples include pigments such as iron oxide, dyes, flame retardants, antioxidants, ultraviolet absorbers, antistatic agents, lubricants, plasticizers, other fillers, and mixtures thereof.

In the present invention, the resin composition consisting of each component can be manufactured by any conventionally known compounding method. For example, melt kneading methods using general kneading machines such as open rolls, intensive mixers, internal mixers, co-kneaders, continuous kneaders with twin rotors, extruders, etc., after dissolving or dispersing each component in a solvent. A method of removing the solvent by heating, etc. is used.

〔Effect of the invention〕

The resin composition of the present invention can be produced by conventionally known molding methods such as extrusion molding, injection molding, blow molding, etc. into sheets, foams, films, injection molded products of various shapes, blow molded products, pressure molded products, vacuum molded products, etc. It can be easily molded into a wide variety of practically useful products such as molded products and biaxially stretched molded products.

In particular, the resin composition of the present invention is effective as a material for sheets and films, and takes advantage of its excellent transparency, impact resistance, and low-temperature properties to be used in food packaging containers, daily goods packaging, and laminated sheets and films. It can also be used.

〔Example〕

Examples of the present invention will be shown below to explain the present invention in more detail, but it goes without saying that the content of the present invention is not limited to these Examples.

Examples 1 to 7 and Comparative Examples 1 to 6 The block copolymers shown in Table 1 were produced according to a conventional method using n-BuLi in cyclohexane as a catalyst.

What is the proportion of components with a molecular weight of 140,000 or more? A block copolymer having the same reamer structure as the main component block copolymer and a molecular weight of about 200,000 was separately manufactured, and this was prepared by blending it.

Next, 15 parts by weight of each block copolymer and 85 parts by weight of polystyrene (using Styron 6851 manufactured by Asahi Kasei Corporation) were thoroughly mixed using a Henschel mixer, and then a sheet with a thickness of 0.35 m was formed using a 4i-sheet extruder. did. The characteristics of the obtained sheet and the thermal stability measurement results of each composition were
Shown in the table.

(Additional colors below) (Note 1) A is a polymer block mainly composed of styrene, and B is a polymer block mainly composed of butadiene.

(Note 1) Based on ASTM D 1709 (Note 3) Based on JIS K 6714 (Note 4) 75 g of the composition was milled using Ugi Plastomill manufactured by Toyo Seiki Co., Ltd.
The mixture was kneaded at 200° C. and 150 rpm, and the time until the torque increased was measured. A long time until torque rise means excellent thermal stability.

Evaluation criteria: 0120 minutes or moreQ! 15 minutes or more, less than 20 minutes 6110 minutes or more, less than 15 minutes × less than ilO minutes Example A sheet was produced in the same manner as in Example 4, except that the blending amounts of the block copolymer and polystyrene were changed. The properties of the obtained sheet and the thermal stability of the composition are shown in Table 2.

Table 2 Example 1O In Example 5, a sheet was prepared in the same manner as in Example 5, except that a block copolymer having a short chain polystyrene content of 2% was used instead of block copolymer E. was created. The dart impact strength of the obtained sheet was 55
Kg-cm. The transparency and thermal stability were equivalent to those of Example 5. The content of short continuous steel polystyrene in block copolymer E was 13.

Examples 11 to 14 After mixing each component according to the proportions shown in Table 3,
A 0.35mm thick sheet was formed using a 40IllI'' extruder. The properties of the resulting sheet and the thermal stability of the composition are shown in Table 3.

(Margin below) (Note 5) Uses Styron 666 manufactured by Asahi Kasei Corporation.

(Note 6) Uses impact-resistant rubber-modified polystyrene produced by bulk polymerization by dissolving polybutadiene in approximately 5 wt % styrene monomer.

Claims (1)

[Scope of Claims] 1 (i) The main component has a molecular weight of 40,000 to 120,000 and a vinyl aromatic hydrocarbon compound content of 10 to 60% by weight;
In addition, 5 to 35 weight % of a block copolymer of a conjugated diolefin and a vinyl aromatic hydrocarbon compound contains a component having a molecular weight of 140,000 or more, and (ii) a non-rubber modified styrenic polymer of 95 to 35 weight %. 65% by weight
Resin composition 2 consisting of (i) the main component has a molecular weight of 40,000 to 120,000 and a vinyl aromatic hydrocarbon compound content of 10 to 60% by weight,
In addition, 5 to 35 weight % of a block copolymer of a conjugated diolefin and a vinyl aromatic hydrocarbon compound contains a component having a molecular weight of 140,000 or more, and (ii) a non-rubber modified styrenic polymer of 95 to 35 weight %. 65% by weight
(iii) A resin composition comprising 2 to 30 parts by weight of a rubber-modified styrenic polymer based on 100 parts by weight of the total amount of component (i) and component (ii).