JP3474386B2 - Resin composition and molded article thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a flexible resin composition having a high degree of gas barrier property and good heat resistance and moldability, and a molded article in which these gas barrier property, heat resistance and flexibility are utilized. Regarding Since the molded product of the present invention has excellent gas barrier properties and heat resistance and has good flexibility, it is useful as a sealing material, a packaging film, a container and the like. Further, the resin composition of the present invention has good moldability (particularly extrusion moldability), and thus is useful as a constituent material of the above-mentioned molded article.

[0002]

2. Description of the Related Art Vinyl chloride resin containing a plasticizer is
Due to its excellent flexibility and gas barrier properties, it is a sealing material,
It is used as a packaging film and container. On the other hand, an unsaturated carboxylic acid or a derivative thereof is added to a hydrogenated product of a block copolymer having a polyolefin resin, an olefin-vinyl alcohol copolymer, and an aromatic vinyl compound polymer block and a conjugated diene polymer block. It is known that a resin composition comprising a modified copolymer obtained by graft polymerization has excellent gas barrier properties and is useful as a material for food packaging (JP-A-1-313).
552). Further, a polyolefin resin, an ethylene-vinyl alcohol copolymer, a polyolefin modified with an unsaturated carboxylic acid or a derivative thereof, and a block copolymer having an aromatic vinyl compound polymer block and a conjugated diene polymer block. It is known that the resin composition comprising the hydrogenated product of 1) has excellent gas barrier properties and is useful as a material for bottles, cups and the like (JP-A-3-277642). In the resin composition containing these polyolefin-based resin and vinyl alcohol-based copolymer, it is derived from a hydrogenated product of a block copolymer having an aromatic vinyl compound-based polymer block and a conjugated diene-based polymer block. In addition, the hydrogenated product of the above modified copolymer, or the above modified polyolefin and the block copolymer having the aromatic vinyl compound polymer block and the conjugated diene polymer block is a polyolefin resin and a vinyl alcohol resin. It is said to have the effect of improving the compatibility with the copolymer.

[0003]

However, the vinyl chloride resin containing the above-mentioned plasticizer is feared to have an adverse effect on the environment due to generation of gas such as hydrogen chloride during incineration. Further, since the plasticizer easily bleeds out, the contents may be contaminated in applications such as packaging films and containers, and the heat resistance is not so high. The polyolefin-based resin, vinyl alcohol-based copolymer, aromatic vinyl compound-based polymer block, and conjugated diene-based polymer block described in JP-A-1-313552 and JP-A-3-277642, respectively. In a resin composition containing a hydrogenated product of a block copolymer having or a modified copolymer derived therefrom, heat resistance is not so high, for example, when the molded product is exposed to high temperature conditions for a long time. May deteriorate and become sticky on the surface.

Therefore, the first object of the present invention is to have a high degree of gas barrier property and heat resistance, yet exhibit good flexibility even when a plasticizer is not added, and have good moldability. and to provide a resin material comprising also.

[0005]

According to the present invention, the above-mentioned first object is (1) (A) a polyolefin resin,
(B) a vinyl alcohol-based copolymer and (C) a block copolymer having an aromatic vinyl compound-based polymer block and an isobutylene-based polymer block, as a main component;

(2) The content of (B) is 10 to 1000 parts by weight relative to 100 parts by weight of (A), and the content of (C) is the same as that of (A) and (B). Gross weight 1
5 to 1000 parts by weight with respect to 00 parts by weight;

It is achieved by providing a resin composition characterized by the following.

[0008]

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

In the present invention, the polyolefin resin used as the component (A) is a homopolymer of an olefin monomer represented by high density polyethylene, low density polyethylene, polypropylene, etc .; ethylene-propylene random copolymer, ethylene-propylene block. Copolymer, ethylene-1-butene copolymer, ethylene-
Examples thereof include copolymers of two or more kinds of monomers such as 1-hexene random copolymer and ethylene-1-octene copolymer. The polyolefin-based resin (A) is not limited to the use of one type of polyolefin-based resin, and two or more types of polyolefin-based resins may be used in combination depending on the purpose.

The vinyl alcohol-based copolymer used as the component (B) in the present invention is a copolymer containing a vinyl alcohol unit (—CH ₂ —CH (OH) —),
Although not necessarily limited, for example, it can be obtained by partially or completely saponifying the corresponding vinyl ester-based copolymer.

The vinyl alcohol copolymer (B) is preferably an olefin-vinyl alcohol copolymer. As the olefin-vinyl alcohol copolymer,
Saponified products of olefin-carboxylic acid vinyl ester copolymers are preferred. The saponified product of the olefin-carboxylic acid vinyl ester copolymer has a molar ratio of olefin unit / carboxylic acid vinyl ester unit of 0.5 / 99.
10-100 mol% of carboxylic acid vinyl ester units by saponifying olefin-carboxylic acid vinyl ester copolymers in the range of 5-99.5 / 0.5
Is preferably a vinyl alcohol unit. The content of olefin units in the saponified product of the olefin-carboxylic acid vinyl ester copolymer is in terms of gas barrier property and molding processability in the resin composition of the polyolefin resin (A) and the block copolymer (C). , 2-70 mol%, preferably 5-65
It is more preferably mol%, and particularly preferably 10 to 60 mol%. The saponification degree (conversion rate of carboxylic acid vinyl ester units to vinyl alcohol units) in the saponified product of the olefin-carboxylic acid vinyl ester copolymer is 90 in terms of gas barrier properties and heat resistance when the resin composition is used. It is preferably at least mol%, more preferably at least 95 mol%, particularly preferably at least 98 mol%. The melt flow rate (measured by the method described in ASTM D1238 under the conditions of a temperature of 190 ° C. and a load of 2.16 kg) in the vinyl alcohol-based copolymer (B) is
From the viewpoint of molding processability in the case of a resin composition,
It is preferably 0.1 to 100 g / 10 minutes, and is 0.1.
More preferably 5 to 50 g / 10 minutes, 1 to 4
It is particularly preferably 0 g / 10 minutes.

Among the saponified products of the olefin-carboxylic acid vinyl ester copolymer, the saponified product of the ethylene-carboxylic acid vinyl ester copolymer is a resin composition of the polyolefin resin (A) and the block copolymer (C). It is particularly preferable from the viewpoints of molding processability and mechanical properties of the product. The saponified product of the ethylene-carboxylic acid vinyl ester copolymer contains a small amount of ethylene units and vinyl alcohol units (preferably 10 mol% based on all constituent units).
The following) may further have other structural units. Other structural units include α-olefins such as propylene, isobutylene, 4-methylpentene-1,1-hexene and 1-octene; vinyl carboxylates such as vinyl acetate, vinyl propionate, vinyl versatate and vinyl pivalate. Esters; unsaturated carboxylic acids such as itaconic acid, acrylic acid, maleic anhydride or derivatives thereof (eg salts, esters, nitriles, amides, anhydrides, etc.); vinylsilane compounds such as vinyltrimethoxysilane; unsaturated sulfonic acids Or a salt thereof; units derived from N-methylpyrrolidone and the like can be mentioned. Further, the saponified product of the ethylene-carboxylic acid vinyl ester copolymer may have a functional group such as an alkylthio group at the terminal of the molecular chain. Among the saponified products of the ethylene-carboxylic acid vinyl ester copolymer, the saponified product of the ethylene-vinyl acetate copolymer is particularly preferable.

The saponification product of an olefin-carboxylic acid vinyl ester copolymer can be produced, for example, by producing an olefin-carboxylic acid vinyl ester copolymer according to a known method and then saponifying it. The olefin-carboxylic acid vinyl ester copolymer includes, for example, a monomer mainly composed of an olefin and a carboxylic acid vinyl ester in an organic solvent such as methanol, t-butyl alcohol, or dimethylsulfoxide under pressure, benzoyl peroxide, and azo. It can be obtained by polymerizing with a radical polymerization initiator such as bisisobutyronitrile. Further, in the saponification of the olefin-carboxylic acid vinyl ester copolymer, an acid catalyst or an alkali catalyst can be used.

The vinyl alcohol-based copolymer (B)
Is not limited to the use of one type of vinyl alcohol-based copolymer, and two or more types of vinyl alcohol-based copolymers may be used in combination depending on the purpose.

The block copolymer used as the component (C) in the present invention contains an aromatic vinyl compound polymer block (a) and an isobutylene polymer block (b). Here, the block (a) is a polymer block derived from a monomer mainly composed of an aromatic vinyl compound. Examples of the aromatic vinyl compound include styrene, p-methylstyrene, α-methylstyrene, and the like.
They can be used alone or in combination of two or more. Block (a) has a number average molecular weight of 3000.
It is preferably in the range of -80,000. On the other hand, the block (b) is a polymer block derived from a monomer mainly composed of isobutylene. The melt flowability of the block copolymer (C) becomes good, and the mixing with the polyolefin resin (A) and the vinyl alcohol copolymer (B) and the subsequent molding become easy. Number average molecular weight is 10,000 to 200,000
And the sum of the weight of the block (a) in the block copolymer (C) is the weight of the block (a) and the block (b) in the block copolymer (C). It is preferably in the range of 10 to 60% with respect to the total sum of The block copolymer (C) is not limited to the use of one type of block copolymer, and two or more types of block copolymers may be used in combination depending on the intended use.

The method for producing the block copolymer (C) is not particularly limited, and for example, hexane,
In an inert solvent such as methylene chloride, in the presence of an initiator system composed of a Lewis acid and an organic compound which forms a cationic polymerization active species in combination with the Lewis acid, polymerization of a monomer mainly composed of an aromatic vinyl compound and It is possible to employ a method in which the polymerization of a monomer mainly containing isobutylene is sequentially performed. Here, examples of the Lewis acid include titanium tetrachloride, boron trichloride, aluminum chloride, tin tetrachloride, and the like. The organic compound forming the cationic polymerization active species is an organic compound having a functional group such as an alkoxy group, an acyloxy group and a halogen atom, and examples thereof include bis (2-methoxy-2-propyl) benzene and bis ( 2-acetoxy-2-propyl)
Examples thereof include benzene and bis (2-chloro-2-propyl) benzene. Furthermore, in the above polymerization method,
If necessary, pyridine; amides such as dimethylacetamide and dimethylformamide may be added to the polymerization reaction system. According to the above-mentioned polymerization method, the block (a) -block (b) -block (a) triblock copolymer is, for example, an initiator composed of a Lewis acid and an organic compound having two functional groups. The system is used to polymerize a monomer mainly composed of isobutylene, and when the polymerization reaction is substantially completed, a monomer mainly composed of an aromatic vinyl compound is added to the polymerization reaction system to continue the polymerization reaction. It can be manufactured by

In the resin composition of the present invention, the content of the vinyl alcohol copolymer (B) is 10 to 1 with respect to 100 parts by weight of the polyolefin resin (A).
000 parts by weight. The content of the block copolymer (C) is 100% by weight of the polyolefin resin (A) and the vinyl alcohol copolymer (B).
It is 5 to 1000 parts by weight with respect to parts by weight. When the content of the vinyl alcohol-based copolymer (B) is less than 10 parts by weight with respect to 100 parts by weight of the polyolefin-based resin (A), depending on the type of the polyolefin-based resin (A) (for example, When the polyolefin resin (A) is low density polyethylene (for example), there is a limit in the level of achieving gas barrier properties. When the content of the vinyl alcohol copolymer (B) exceeds 1000 parts by weight with respect to 100 parts by weight of the polyolefin resin (A), flexibility may be insufficient. When the content of the block copolymer (C) is less than 5 parts by weight based on 100 parts by weight of the total weight of the polyolefin resin (A) and the vinyl alcohol copolymer (B), the flexibility is insufficient. To do. In addition, the content of the block copolymer (C) is (A) and (B) above.
If it exceeds 1000 parts by weight based on 100 parts by weight, the flexibility of the resin composition becomes too high, which makes it unsuitable as a raw material for molded articles that are required to have self-shape retention. The content of the vinyl alcohol-based copolymer (B) is 100 parts by weight of the polyolefin-based resin (A) based on the reason that the appropriate flexibility and the extremely high gas barrier property as described above can be achieved at a very high level. 20 to 500 parts by weight, and the content of the block copolymer (C) is 10 to 50 parts by weight based on 100 parts by weight of the total weight of the polyolefin resin (A) and the vinyl alcohol copolymer (B).
It is preferably part by weight.

In the present invention, the resin composition may be added to the resin composition, if necessary, to the extent that the effects of the present invention are not lost.
In addition to the polyolefin resin (A), the vinyl alcohol copolymer ( B ) and the block copolymer (C), other components may be blended. For example, for the purpose of improving heat resistance, weather resistance or increasing the amount, calcium carbonate,
Inorganic fillers such as talc, carbon black, titanium oxide, silica, clay, barium sulfate and magnesium carbonate can be added. In order to improve the surface lubricity of a molded product from a resin composition, an aliphatic hydrocarbon lubricant such as polyolefin wax, a higher aliphatic alcohol, a higher fatty acid lubricant, a fatty acid amide such as an amide or bisamide of a higher fatty acid Lubricants, metal soap-based lubricants such as calcium stearate, and the like can be added. In addition, a heat stabilizer, an antioxidant, a light stabilizer and the like can be added.

The method of mixing the respective components for preparing the resin composition of the present invention is not particularly limited, and the same method as in the production of ordinary polyolefin resin compositions can be adopted.

Among them, when the polyolefin resin (A), the vinyl alcohol copolymer (B) and the block copolymer (C) are mixed under melting conditions,
It is preferable to use this mixing method because the gas barrier property of the obtained resin composition is further enhanced. When the mixing method under the melting condition is adopted, the gas barrier property of the resin composition becomes particularly high. Therefore, the components (A), (B) and (C) have the same temperature as the melting condition. [A] and [b] are melt viscosities when measured under a shear rate of 100 sec ^-1 in
And [c], [a]> [b] and [c]
It is preferable to use one satisfying the condition of [b]. As a method for mixing the components (A), (B) and (C) under melting conditions, for example, a method comprising melt-mixing the respective components at a predetermined ratio using a melt-kneader such as an extruder or a kneader. Can be adopted. The heating temperature in mixing under these melting conditions may be a temperature above the temperature at which each component melts and flows, and in a range that does not substantially cause thermal deterioration, and is generally 150 to 300.
It is possible to employ a temperature in the range of 0 ° C, more preferably in the range of 180 to 280 ° C.

Since the resin composition of the present invention has good moldability, it can be molded into a molded product having a desired shape and size by various molding methods. As a molding method, injection molding, extrusion molding, compression molding, blow molding, vacuum molding, or the like can be adopted according to a known method. Further, examples of the molded product include molds, sheets, films, pipes, bottle-shaped products and the like. INDUSTRIAL APPLICABILITY The resin composition of the present invention can exhibit excellent moldability in melt extrusion molding, particularly in melt extrusion film formation, and it is possible to obtain a molded product having a good surface condition. A molded article comprising the resin composition of the present invention has a sealing material, in order to have appropriate flexibility, good heat resistance and high gas barrier properties.
It is useful as a packaging film, container, etc.

[0023]

EXAMPLES Next, the present invention will be specifically described with reference to examples. In addition, "part" in each Example represents a "weight part."

The melt viscosity of the components of the resin composition is measured and the resin composition is evaluated by the following methods (1) to (5).
Went by.

(1) Melt viscosity For each component of the resin composition, a shear rate of 10 at the same temperature as the melt-kneading for preparing the resin composition.
The melt viscosity under the condition of 0 sec- ¹ was measured by a capillary rheometer ("Caprograph 1C" manufactured by Toyo Seiki Seisaku-sho, Ltd.).

(2) The flexible resin composition was compression-molded under a temperature condition 20 ° C. higher than the melting temperature to prepare a sheet having a thickness of 6 mm. Using this, the hardness (Shore D) is measured according to JIS K7215. For those having a Shore D hardness of 35 or less, the hardness (Shore D) is further measured according to JIS K6301 (J
ISA) was measured. These hardnesses were used as an index of flexibility.

(3) The heat-resistant resin composition of the molded product is compression-molded to prepare a sheet-like test piece having a length of 20 cm, a width of 20 cm, and a thickness of 2 mm.
After being placed in a gear oven at 0 ° C. for 24 hours, it was cooled to room temperature and touched with a finger to examine the stickiness of the surface of the test piece. The same as before heating, "very good" (◎) when no stickiness is observed, "good" (○) when almost no stickiness is observed, "slightly inferior" (△) when slightly sticky is observed, Heat resistance was evaluated by judging the degree of thermal deterioration in four stages of "poor" (x) in the case of severe stickiness.

(4) Using the gas barrier resin composition, compression molding was carried out under a temperature condition 20 ° C. higher than the melting temperature to prepare a film having a thickness of 200 μm. About this film, an oxygen pressure of 2.5 k was measured using a gas permeability measuring device (“GTR-10” manufactured by Yanagimoto Seisakusho).
Oxygen permeation coefficient P under conditions of g / cm ² and temperature of 35 ° C.
o ₂ was measured and used as an index of gas barrier property.

(5) Using the film-forming resin composition, a film was formed by a 20 mmφ Labo Plastomill film forming machine (manufactured by Toyo Seiki Seisakusho) at a temperature of 230 ° C. and a screw rotation speed of 100 rpm. The surface roughness of the obtained film was visually observed. "Extremely good" (◎) when the surface is extremely smooth, "Good" (○) when the surface is only slightly rough, and "Poor" (X) when the surface is rough like shark skin. Film formability was evaluated by determining the surface condition in three stages.

The polyolefin resins used in the examples are indicated by the following abbreviations.

Polyolefin resin (A-1): Low density polyethylene ("Mirason 401" manufactured by Mitsui Petrochemical Co., Ltd.) Polyolefin resin (A-2): Propylene-ethylene block copolymer (Mitsubishi Chemical "Mitsubishi Polypro BC-")
3 ") Polyolefin resin (A-3): Low density polyethylene (" Mirason 68 "manufactured by Mitsui Petrochemicals) Polyolefin resin (A-4): Low density polyethylene (" Mirason B319 "manufactured by Mitsui Petrochemicals) Polyolefin resin (A -5): Ethylene-1-octene copolymer (“Engage EG820” manufactured by Dow Chemical Co., Ltd.
0 ")

The vinyl alcohol copolymers used in the examples are shown by the following abbreviations.

Vinyl alcohol-based copolymer (B-1):
Ethylene-vinyl alcohol copolymer (Kuraray's "Eval EP-E105") Vinyl alcohol copolymer (B-2): ethylene-vinyl alcohol copolymer (Kuraray's "Eval EP-G"
110 ")

The block copolymers used in the examples are indicated by the following abbreviations.

Block copolymer (C-1): triblock copolymer of polystyrene block-polyisobutylene block-polystyrene block (number average molecular weight 340
00, molecular weight distribution (Mw / Mn) 1.23, polystyrene block content 30% by weight) Block copolymer (C-2): polystyrene block-
Polyisobutylene block-polystyrene block triblock copolymer (number average molecular weight 75,000, molecular weight distribution (Mw / Mn) 1.20, polystyrene block content 20% by weight) Block copolymer (C-3): polystyrene block-
Polyisobutylene block-polystyrene block triblock copolymer (number average molecular weight 76000, molecular weight distribution (Mw / Mn) 1.27, polystyrene block content 30% by weight) Block copolymer (C-4): polystyrene block-
Ethylene / propylene copolymer block-polystyrene block triblock copolymer (Kuraray's Septon 2007)

Examples 1 to 9 and Comparative Examples 1 to 3 The polyolefin resin (A), vinyl alcohol copolymer (B), block copolymer (C) and other block copolymers are shown in the table. 1 or premixed at the ratio shown in Table 2, and then kneaded under a melting condition at a temperature of 220 ° C. using a twin-screw extruder to obtain a resin composition. The evaluation results of the obtained resin composition are shown in Table 1 and Table 2.
Shown in.

[0037]

[Table 1]

[0038]

[Table 2]

In Tables 1 and 2 above, "a", "b" and "c" in the column "large or small melt viscosity" are as follows:
It means the melt viscosity of the polyolefin resin (A), the melt viscosity of the vinyl alcohol copolymer (B) and the melt viscosity of the block copolymer (C), respectively.

From the above Tables 1 and 2, the resin compositions according to the present invention described in Examples 1 to 9 have an oxygen permeability coefficient of 5800cc · 20 μm / m ² · day · atm or less, so that they are highly gasses. It can be seen that the film has barrier properties, and that it has a Shore D hardness of 52 or less and a JIS A hardness of 75 or more, and thus has appropriate flexibility. Furthermore, since the heat resistance evaluation result is "○" (good), there is no problem in heat resistance, and the film moldability evaluation result is "◎" (extremely good) or "○" (good). From this, it can be seen that there is no problem in extrusion moldability. In addition, Table 1
From Table 2 and Table 1, among Examples 1 to 9, the melt viscosity (b) of the vinyl alcohol-based copolymer (B) is the same as that of the polyolefin resin (A) and the block copolymer (C). When the melt viscosity is lower than either of the melt viscosity (c) (Examples 1 to 4 and Examples 6 to 9), the oxygen permeability coefficient is 2400 cc · 20 μm / m ² · day · atm or less.
It can be seen that the gas barrier property is particularly excellent. on the other hand,
In the resin compositions described in Comparative Examples 1 and 2, which do not contain the vinyl alcohol-based copolymer (B) or differ from the present invention in that the blending ratio thereof is too low,
Since the oxygen permeability coefficient is 12000 cc · 20 μm / m ² · day · atm, it is understood that the gas barrier property is lower than that of the present invention. In addition, in the resin composition of Comparative Example 3 in which the block copolymer is different from the block copolymer (C) in the present invention, the heat resistance evaluation result is “Δ” (poor), and the film moldability is evaluated. Since the result is "x" (defective), it is understood that the heat resistance and the film moldability are insufficient.

[0041]

EFFECT OF THE INVENTION The resin composition of the present invention has appropriate flexibility, and further has high gas barrier properties, good heat resistance and good moldability. Therefore, a molded article made of the resin composition effectively exhibits these excellent properties,
It is effectively used as a sealing material, a packaging film, a container, etc. used under high temperature conditions.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-10-195270 (JP, A) JP-A-1-315442 (JP, A) JP-A-1-313552 (JP, A) JP-A-3- 277642 (JP, A) JP 7-3089 (JP, A) JP 10-1579 (JP, A) JP 10-110086 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 23/00-23/36 C08L 29/04 C08L 53/00-53/02

Claims (2)

(57) [Claims] (1) (A) a polyolefin resin,
(B) A vinyl alcohol-based copolymer and (C) a block copolymer having an aromatic vinyl compound-based polymer block and an isobutylene-based polymer block are contained as main components; (2) The inclusion of (B) above The amount is 10 to 1000 parts by weight based on 100 parts by weight of (A), and the content of (C) is 5 to 1000 parts by weight based on 100 parts by weight of the total weight of (A) and (B). A resin composition. 2. (1) (A) a polyolefin resin,
(B) A vinyl alcohol-based copolymer and (C) a block copolymer having an aromatic vinyl compound-based polymer block and an isobutylene-based polymer block are contained as main components; (2) The inclusion of (B) above The amount is 10 to 1000 parts by weight based on 100 parts by weight of (A), and the content of (C) is 5 to 1000 parts by weight based on 100 parts by weight of the total weight of (A) and (B). (3) Obtained by mixing (A), (B) and (C) above under melting conditions; (4) Melting conditions for (A), (B) and (C) above When the melt viscosities when measured under the conditions of a shear rate of 100 sec- ^{1 at} the same temperature as the above are represented by [a], [b] and [c] respectively, [a]>
A resin composition satisfying the conditions of [b] and [c]> [b].