JPH06263943A - Styrenic resin composition and sheet made of the composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition having excellent transparency and impact resistance and suitable for food packaging, etc., by adding petroleum resin, etc., to a mixture of a vinyl aromatic compound-conjugated diene block copolymer and a styrene-methacrylate copolymer. CONSTITUTION:This styrenic resin composition is produced by adding 0.1-15 pts.wt. of one or more kinds of resins such as (hydrogenated) petroleum resin and (hydrogenated) coumarone resin to 100 pts.wt. of a mixture of (A) 99-30 pts.wt. of a block copolymer containing 60-90wt.% of a polymer block composed mainly of a vinyl aromatic hydrocarbon expressed by the formula (A-B)nZ (A is vinyl aromatic hydrocarbon polymer block; B is conjugated diolefin polymer block; Z is residue of polyfunctional coupling agent used for forming a star polymer; (n) is the number of functional groups of the polyfunctional coupling agent and is an integer of >=3) and 40-10wt.% of a polymer block composed mainly of a conjugated diolefin and (B) 1-70 pts.wt. of a styrene- methacrylate copolymer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a styrene resin composition and a sheet or film which are transparent and have excellent impact resistance, which are used for food packaging containers, blister packs, general container cases and the like.

[0002]

2. Description of the Related Art Conventionally, in order to obtain a transparent and high-impact styrenic resin, a method of mixing polystyrene and a styrene / butadiene block copolymer (JP-A-51-10).
3956, JP-A-55-157642)
Alternatively, a method of mixing a radial styrene-butadiene block copolymer and a styrene-methacrylic acid ester copolymer is well known. However, these methods have a drawback that the transparency is lowered, and if the transparency is satisfactory, the impact strength is insufficiently improved and the use is limited.

Further, when a resin composition comprising such a mixture is applied to an injection-molded article, a molded article having a good balance of transparency and impact resistance can be obtained. It has been found that a pear-like pattern such as frosted glass may be generated on the surface to reduce the transparency of the sheet. As described above, the conventional techniques still have room for improvement, and the excellent properties of the styrene resin, such as moldability and rigidity, cannot be fully utilized, and its use in the fields required by the market is limited.

[0004]

An object of the present invention is to provide a styrene resin composition excellent in transparency and impact strength, and a sheet or film thereof.

[0005]

As a result of various studies to overcome the problems of the prior art, the present inventor has found that a vinyl aromatic hydrocarbon-conjugated diolefin block copolymer (hereinafter referred to as styrene-butadiene block copolymer). (Sometimes abbreviated as "combination") and a styrene-methacrylic acid ester copolymer, (a) petroleum resin, (b) hydrogenated petroleum resin (also known as hydrogenated petroleum resin), (c) Coumarone resin,
(D) A resin composition which is transparent and has high impact resistance by uniformly blending at least one kind of resin selected from hydrogenated coumarone resin (also known as hydrogenated coumarone resin) and a film or sheet thereof The inventors have found that the following can be obtained and have reached the present invention.

That is, according to the present invention, the content of the polymer block mainly composed of vinyl aromatic hydrocarbon is 60 to 90% by weight and the content of the polymer block mainly composed of conjugated diolefin is 40 to 10% by weight. A resin block copolymer having a low rubber content selected from a linear block copolymer or a radial branched block copolymer
100 parts by weight of a mixture of 1 part by weight and 1 to 70 parts by weight of a styrene-methacrylic acid ester copolymer,
(A) petroleum resin, (b) hydrogenated petroleum resin, (c)
A transparent and high-impact styrene resin composition containing at least one resin selected from coumarone resin and (d) hydrogenated coumarone resin in a proportion of 0.1 to 15 parts by weight, and a sheet thereof. Or a film.

The present invention will be described in detail below. The block copolymer referred to in the present invention is a block copolymer having a linear or branched structure, which is represented by the general formula (A-
B) n, A- (BA) n, B- (AB) n represented by the linear block copolymer, and general formula (AB) mZ represented by the branched block copolymer. There is coalescence etc. In the formula, A
Is a polymer block mainly containing vinyl aromatic hydrocarbons, and B is a polymer block mainly containing conjugated diolefins. n is 1 or more and is generally an integer of 1 to 5. Z in the formula represents a residue or a reaction product of the polyfunctional coupling agent used for forming the radial polymer, and m represents the number of functional groups of the polyfunctional coupling agent and is at least 3 It is an integer above the above. Further, the polymer block mainly composed of vinyl aromatic hydrocarbon is styrene, dimethylstyrene,
It is a polymer block composed of a vinyl aromatic hydrocarbon compound such as vinyltoluene, α-methylstyrene, vinylnaphthalene, etc., and is generally a styrene polymer block.

The polymer block containing a conjugated diolefin as a main component is a polymer block composed of a conjugated diene compound such as butadiene, isoprene and 1,3-pentadiene. Examples of the polyfunctional coupling agent used for forming the radial polymer used for forming Z, which is the central atom or central atomic group of the radial branched block copolymer, include polyepoxides, polyisocyanates, polyisocyanates, and polyisocyanates. Aldehydes, polyketones, polyamines, tin compounds such as tetraallyltin and stannic fluoride are trifunctional or more.

Further, in the block copolymer, the ratio of the vinyl aromatic hydrocarbon polymer block A and the conjugated diene polymer block B is 60 to 90% by weight for the A segment and 40 to 10 for the B segment. There is no particular limitation as long as it is a resinous block copolymer having a low rubber content, which is composed of wt%. Usually, those having a melt index (MI) of 0.5 g / 10 minutes or more are used. MI is 0.
When it is less than 5 g / 10 minutes, moldability is deteriorated and difficulty is increased. If the A segment is less than 60% by weight, the rigidity is poor, and if the B segment is less than 10% by weight, the impact resistance is poor, which is not preferable. As a specific method for producing these block copolymers, Japanese Patent Publication No.
14979, Japanese Patent Publication No. 48-4106, Japanese Patent Publication No. 49-
An example thereof is described in detail in Japanese Patent Publication No. 86959.

The styrene-methacrylic acid ester-based copolymer used in the present invention is at least one styrene-based monomer such as styrene or α-methylstyrene, and methyl methacrylate, ethyl methacrylate or methacrylic acid. It is a copolymer with at least one methacrylic acid ester such as butyl. Specifically, styrene-methylmethacrylate copolymer, styrene-ethylmethacrylate copolymer, styrene / α-methylstyrene-methylmethacrylate copolymer, styrene-methylmethacrylate / butylmethacrylate copolymer, etc. Is.

Of these, for applications where transparency and impact resistance are desired, the content of methacrylic acid ester is 3 to 30.
It is preferably in the range of 5 to 20% by weight, more preferably 5 to 20% by weight. The impact resistance depends on the content of methacrylic acid ester, and if the content is less than 3% by weight, improvement in impact cannot be expected. On the other hand, if it exceeds 30% by weight, a pear-skin pattern such as frosted glass is likely to occur on the surface of a sheet or the like, and the transparency is likely to be deteriorated. The molecular weight of the styrene-methacrylic acid ester-based copolymer is not particularly limited, but the reduced viscosity is 0.3d from the viewpoint of improving productivity and impact resistance.
A value of 1 / g or more, preferably 0.5 to 1.1 dl / g is practical. These styrene-methacrylic acid ester-based copolymers can be easily produced by a bulk polymerization method or a solution polymerization method by changing the ratio of the monomers.
At that time, the reduced viscosity of the copolymer can be adjusted by appropriately changing the polymerization temperature, the initiator, the solvent and the like, or adding a chain transfer agent.

In the present invention, the styrene-methacrylic acid ester copolymer is 1 to 70% by weight with respect to 99 to 30% by weight of the styrene-butadiene block copolymer.
The styrene-methacrylic acid ester-based copolymer is preferably used in a proportion of 5 to 50% by weight. The styrene-methacrylic acid ester-based copolymer improves the rigidity of the styrene-butadiene-based block copolymer, but if the mixing ratio exceeds 70% by weight, the impact resistance of the mixture becomes too low, which is preferable. Absent.

(A) petroleum resin to be used alone or in combination with the mixture of the copolymer of the present invention,
(B) hydrogenated petroleum resin, (c) coumarone resin,
(D) The hydrogenated coumarone resin will be described. Petroleum resin is also called petroleum-based hydrocarbon resin, and there are the following types because a cracked oil fraction containing a large number of unsaturated hydrocarbons by-produced by thermal decomposition of naphtha is polymerized. Of the cracked oil fractions, those derived from the C5 fraction are aliphatic or C5 petroleum resins, those derived from the C9 fraction are aromatic or C9 petroleum resins, and those derived from both are C
It is called 5C9 copolymer petroleum resin. Among C5-based petroleum resins, cyclopentadiene-based petroleum resin (cycloaliphatic petroleum resin)
Others may be called differently from the aliphatic petroleum resin. Since the mixed fractions are all used as raw materials, their chemical structures cannot be determined unconditionally, but they are typically as follows.

The main component of the C5 petroleum resin is a copolymer of isoprene, pentadiene, piperylene, pentene, methylbutene and the like, and the conjugated diolefin often has a cyclized structure. A softening point of 70 to 100 ° C. is common. The main components of C9 petroleum resin are styrene, vinyltoluene, α, β-
Copolymer of methylstyrene, indene, etc. with a softening point of 80
A temperature of ~ 150 ° C is common. The C5C9 copolymer petroleum resin is a copolymer of the above C5 and C9 and has a softening point of 60 to 100 ° C.
Is common. In addition, some of these petroleum resins have an ester group, a hydroxyl group, a carboxyl group or the like introduced therein.

The coumarone resin, which is also called coumarone / indene resin, is made from solvent naphtha contained in light oil in coke oven gas as a raw material, and styrene, coumarone,
It is a copolymer such as indene and has a softening point of 70 to 160 ° C or higher. Hydrogenated petroleum resin (also known as hydrogenated petroleum resin) and hydrogenated coumarone resin (also known as hydrogenated coumarone resin) are those obtained by hydrogenating the aforementioned petroleum resin and coumarone resin by a conventional method. . The hydrogenation rate (hydrogenation rate) is not particularly limited, but is 2 when the hue is important.
0% or more is preferable.

At least one of these (a) petroleum resin, (b) hydrogenated petroleum resin, (c) coumarone resin, and (d) hydrogenated coumarone resin may be used alone or in combination. it can. Further, it is possible to use one or more kinds having the same kind but different softening points in combination. Moreover, you may use the thing of a predetermined hydrogenation rate (hydrogenation rate), and it can mix and use what was 100% hydrogenated and what is not. For example, when the hue or odor is important, C5 petroleum resin, hydrogenated petroleum resin, hydrogenated coumarone resin may be mainly selected. If heat resistance is important, hydrogenated petroleum resin or hydrogenated coumarone resin may be selected, and if blocking resistance or hardness improvement is important, C9 petroleum resin may be selected.

The above-mentioned (a) petroleum resin, (b) hydrogenated petroleum resin, (c) coumarone resin, and (d) hydrogenated coumarone resin have hitherto been known as moldability, tackiness and heat resistance of polyolefin resin. It is used as a modifier for sealing properties (Japanese Patent Laid-Open Nos. 48-49835 and 58-1).
No. 85635, JP-A-60-90734, etc.) to improve transparency and impact resistance by adding to the mixture of the styrene-butadiene block copolymer and the styrene-methacrylic acid ester copolymer in the present invention. Utilization as a substance is not yet known.

These resins or resins in combination thereof may be added in an amount of 0.1 to 15 parts by weight based on 100 parts by weight of a mixture of a styrene-butadiene block copolymer and a styrene-methacrylic acid ester copolymer. desirable. If the amount of these resins is less than 0.1 parts by weight, the effect is difficult to be exhibited, and if it exceeds 15 parts by weight, the tackiness becomes too strong, the blocking phenomenon occurs, and the transparency deteriorates, which is not preferable.

The styrene resin composition of the present invention or a film or sheet obtained from the styrene resin composition includes a stabilizer, an antioxidant, an ultraviolet absorber, an antistatic agent, an antifogging agent, an antiblocking agent, and a release agent. , Colorants, fillers and the like can be added depending on the purpose. In the present invention, the blending method of each component is not particularly limited, and may be performed according to a conventional method, for example, a known melt-kneading method such as a continuous kneader with a twin-screw rotor, an extruder, a calendar roll, a Banbury mixer can be used.

The resin composition obtained can be molded into various molded products by injection molding or extrusion molding. Further, it can be formed into a sheet or a film by using a T die sheet extruder, a cast processing device, a biaxial stretching processing device, an inflation processing device and the like. The obtained molded product is used for covers, cases, daily sundries, etc. by utilizing its excellent transparency and impact resistance. It is particularly effective as a material for styrene resin sheets and films, and can be suitably used as a food packaging container, daily sundries packaging, and lamination sheet film.

[0021]

In the present invention, a mixture of a block copolymer composed of a vinyl aromatic hydrocarbon and a conjugated diolefin and a styrene-methacrylic acid ester copolymer is used for a petroleum resin, a coumarone resin or a mixture thereof. Hydrogenated resin,
By blending at least one resin selected from the following, the balance between transparency and impact resistance is greatly improved.

[0022]

EXAMPLES Specific examples of the present invention will be described below.
In the examples, parts and% are by weight unless otherwise specified. Further, the test methods for measuring physical properties in Examples and the like are as follows. (1) Sheet molded product Drop weight impact test: In accordance with JIS K7124. Transparency (haze, etc.) measurement: Based on JIS K6714. Judgment of blocking phenomenon: Five or six molded sheets were stacked and left at 60 ° C. for 3 days while applying a load of 2 kg. Then, the following evaluations were performed based on the state of sound generation when the sheet was peeled by hand. [Evaluation] ◯: Good (no sound generation and no blocking). Δ: Normal (a small sound is generated and some blocking occurs). ×: No (a loud sound is generated and glocking is severe). (2) Injection-molded product Tensile test: In accordance with ASTM D638. Bending test: According to ASTM D790. Izod impact test: According to ASTM D256. Transparency (haze, etc.) measurement: Based on JIS K6714.

Examples 1 to 7 and Comparative Examples 1 to 5 According to the formulation shown in Table 1, pellets were first prepared using an extruder. Then, the obtained composition was molded into a sheet having a thickness of 0.6 mm using a 40 mmφ single screw extruder.
A test piece having a predetermined size was prepared by cutting out with a dumbbell cutter. The measurement results are summarized in Table 1.

Examples 8 to 18 and Comparative Examples 6 to 9 Using the formulation shown in Table 2, the same operations as in the above Examples were carried out and the sheet molded products were evaluated. The results are shown in Table 2.

Examples 19 to 21 and Comparative Examples 10 to 12 According to the formulation shown in Table 3, pelletization was carried out using an extruder. Then, the composition was injected into an injection molding machine (clamping force 1
The test piece was molded at 00t). A flat plate having a thickness of 3 mm was used for measuring the transparency. The results are shown in Table 3.

[0026]

[Table 1] [Note] 1) Component A: styrene-butadiene block copolymer a) Philips Petroleum, K-resin KR03: radial branch type, styrene content 75%. b) Asaflex 810 manufactured by Asahi Kasei: Linear type, styrene content 70%. 2) Component B Styrene-methyl methacrylate copolymer c) Nippon Steel Chemical Co., Ltd., Estyrene KS-10: Methyl methacrylate content 10%. d) Nippon Steel Chemical Co., Ltd., styrene prototype: polystyrene containing 20% methyl methacrylate e) Nippon Steel Chemical Co., Ltd., styrene G14. 3) Component C f) Arakawa Chemical Co., Alcon P-125: Hydrogenated C9 petroleum resin, softening point 125 ° C.

[0027]

[Table 2] [Note] 1) Component A: Styrene-butadiene block copolymer made by Philips Petroleum, K-resin KR03: radial branch type, styrene content 75%. 2) B component: styrene-methyl methacrylate copolymer manufactured by Nippon Steel Chemical Co., Ltd., styrene-10% content of methyl methacrylate 3) C component g) manufactured by Arakawa Chemical Co., Ltd., Alcon P-90: hydrogenated C9 system Petroleum resin, softening point 90 ° C h) Arakawa Chemical Co., Alcon M-135: partially hydrogenated C9 petroleum resin, softening point 135 ° C. i) Idemitsu Petrochemical, Admarb P-125: Hydrogenated C5
C9 petroleum resin, softening point 125 ° C. j) manufactured by Nippon Zeon, Quinton A100: C5 petroleum resin (aliphatic), softening point 100 ° C. k) Quinton U185: C5C9 petroleum resin manufactured by Zeon Corporation, softening point 86 ° C. 1) Quinton 1500: C5 petroleum resin (modified alicyclic group) manufactured by Nippon Zeon, softening point 100 ° C. m) manufactured by Nippon Steel Chemical Co., Ltd., S-Crystal A-120S: hydrogenated coumarone resin, softening point 120 ° C. n) Nippon Steel Chemical Co., Ltd., Esclon G-90: coumarone resin, softening point 90 ° C. o) Nippon Petrochemical, Neopolymer L-90: C9 petroleum resin, softening point 90 ° C. p) Maruzen Petrochemical, Marukalets H-925: hydrogenated alicyclic petroleum resin, softening point 125 ° C. q) Quinton A100 / Neopolymer L-90 = 2 parts / 2 parts mixed.

[0028]

[Table 3] [Note] 1) Component A: Styrene-butadiene block copolymer made by Philips Petroleum, K-resin KR03: radial branch type, styrene content 75%. 2) Component B: Styrene-methyl methacrylate copolymer manufactured by Nippon Steel Chemical Co., Ltd., Estyrene KS-10: Methyl methacrylate content 10% 3) Component C: Kumaron resin manufactured by Nippon Steel Chemical Co., Ltd., Esclon G-90: Softened Point 90 ° C.

From the results of the above examples and comparative examples, (1) by adding various petroleum resins, coumarone resins and their hydrogenated resins, impact resistance is remarkably improved without impairing transparency. You can see that you can. This effect was confirmed even in the injection molded product, but it was particularly remarkable in the extrusion molded product (sheet). (2) It can be seen that if the addition amount of these is too small, the effect is not exhibited, and if the addition amount is too large, there is an effect, but blocking is likely to occur, and the transparency tends to decrease. (3) When the amount of styrene-methacrylic acid ester mixed is increased, the effect of improving impact resistance is reduced, and when the amount is too large, the effect is hardly exhibited.

[0030]

According to the present invention, a block copolymer comprising a vinyl aromatic hydrocarbon and a conjugated diolefin,
(A) petroleum resin, (b) hydrogenated petroleum resin, (c) coumarone resin, (d) hydrogenated coumarone resin, for a mixture of styrene and a copolymer of methacrylic acid ester, By blending at least one kind of resin selected from the above, a transparent and high-impact styrene resin composition and a molded article thereof can be obtained. In particular, the film or sheet molded article obtained from the composition of the present invention has a significantly improved balance between transparency and impact resistance and has excellent performance. Therefore, it is used as covers, cases, daily sundries, etc. as applications, and is particularly effective as a material for styrene resin sheets and films, such as food packaging containers, blister packs, daily sundries packaging, lamination sheet films, etc. Can be suitably used as.

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area C08L 45:00)

Claims (3)

[Claims] 1. A resin comprising a content of polymer blocks mainly composed of vinyl aromatic hydrocarbons of 60 to 90% by weight and a content of polymer blocks mainly composed of conjugated diolefins of 40 to 10% by weight. Block copolymer 99 to 30 parts by weight and styrene-methacrylic acid ester copolymer 1
At least selected from (a) petroleum resin, (b) hydrogenated petroleum resin, (c) coumarone resin, and (d) hydrogenated coumarone resin with respect to 100 parts by weight of the mixture with ˜70 parts by weight. A styrene resin composition containing one type of resin in a proportion of 0.1 to 15 parts by weight. 2. A block copolymer having the general formula (AB) n
Z (in the formula, A is a vinyl aromatic hydrocarbon polymer block having a content of 60 to 90% by weight, B is a conjugated diene polymer block having a content of 40 to 10% by weight, and Z is Represents a residue or a reaction product of a polyfunctional coupling agent used for forming a radial polymer, and n represents the number of functional groups of the polyfunctional coupling agent and is an integer of at least 3 or more.) The styrene resin composition according to claim 1, which is a radial branched block copolymer represented by: 3. A sheet or film obtained by extruding the styrene resin composition according to claim 1 or 2.