JP3393925B2 - Thermoplastic resin composition - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thermoplastic resin composition, and more particularly to a thermoplastic resin composition which is excellent in flexibility, mechanical strength and high frequency welder characteristics and which is particularly suitable for film applications.

[0002]

TECHNICAL BACKGROUND OF THE INVENTION Soft polyvinyl chloride resin (soft P
Since VC) is flexible and excellent in transparency and can be subjected to high-frequency welder (high-frequency welding) processing, it is widely used for applications such as small cases, files, and covers for coating. However, since soft PVC products generate corrosive gas when they are incinerated as waste, development of alternative materials has been strongly desired.

By the way, an ethylene / unsaturated ester copolymer is known as a transparent and flexible material like soft PVC, but the ethylene / unsaturated ester copolymer is not always good in elastic recovery. If the high frequency welder characteristics of the ethylene / unsaturated ester copolymer are to be improved, it is necessary to increase the ratio of unsaturated ester in the ethylene / unsaturated ester copolymer. The ethylene / unsaturated ester copolymer having a high content has problems that it has low mechanical strength and is apt to cause blocking.

For this reason, the present inventors have characteristics such as excellent flexibility, transparency, and high frequency welder characteristics comparable to those of soft PVC, and have appropriate tensile strength when stretched and elastic recovery force. In order to provide an excellent non-PVC material, the inventors have made earnest studies.

As a result, the specific ethylene copolymer (A)
And a specific ethylene / unsaturated ester / carbon monoxide copolymer (B) have characteristics such as excellent flexibility, transparency, and high frequency welder characteristics comparable to those of flexible PVC. Moreover, they have found that they have an appropriate tensile strength when stretched, are excellent in elastic recovery, and are unlikely to cause blocking, and completed the present invention.

[0006] The patent application is published, 5012, 1985
The 18 JP, carbon monoxide in an amount of 0.1 to 50% "olefin / olefinically unsaturated C ₃ -C ₅ organic acid or a lower alkyl ester / carbon monoxide terpolymer It is described that the copolymer has a high-frequency electromagnetic radiation heat sealing property (high-frequency welder property).

[0007]

SUMMARY OF THE INVENTION The present invention is intended to solve the problems associated with the prior art as described above, and has characteristics such as excellent flexibility, transparency and high frequency welder characteristics comparable to those of flexible PVC. In addition, it has a suitable tensile strength when stretched, has an excellent elastic recovery, is unlikely to cause blocking, and can be used in the fields where soft PVC has been used in the past, and is a novel type that does not generate harmful gas during incineration. It is intended to provide a thermoplastic resin composition.

[0008]

SUMMARY OF THE INVENTION A thermoplastic resin composition according to the present invention comprises 50 to 99 parts by weight of an ethylene copolymer (A) and ethylene.
Unsaturated ester / carbon monoxide copolymer (B) 50 to 1 part by weight [total of (A) and (B) is 100 parts by weight]
A resin composition comprising: (i) an ethylene / unsaturated ester / unsaturated carboxylic acid copolymer, an ethylene / unsaturated ester copolymer, and an ethylene / unsaturated resin. A mixture of two or more kinds selected from the group consisting of carboxylic acid copolymers, or (ii) an ethylene / unsaturated ester / unsaturated carboxylic acid copolymer, wherein the ethylene copolymer is (A) contains 50 to 95% by weight of ethylene units, 1 to 40% by weight of unsaturated ester units, and 1 to 20% by weight of unsaturated carboxylic acid units. Is characterized by.

This thermoplastic resin composition has characteristics such as excellent flexibility, transparency and high-frequency welder characteristics comparable to those of soft polyvinyl chloride resin, and has a proper tensile strength when stretched. It has excellent elastic recovery, is less likely to cause blocking, can be used in fields where soft PVC has been used in the past, and does not generate harmful gas when incinerated.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The thermoplastic resin composition according to the present invention will be specifically described below. The thermoplastic resin composition according to the present invention comprises 50 to 99 parts by weight of the following ethylene copolymer (A) and 50 to 1 parts by weight of ethylene / unsaturated ester / carbon monoxide copolymer (B). The total of (A) and (B) is 100 parts by weight].

[Ethylene Copolymer (A)] This ethylene copolymer (A) includes (i) an ethylene / unsaturated ester / unsaturated carboxylic acid copolymer, an ethylene / unsaturated ester copolymer and an ethylene / unsaturated ester copolymer. It is a mixture of two or more kinds selected from the group consisting of unsaturated carboxylic acid copolymers, or (ii) an ethylene / unsaturated ester / unsaturated carboxylic acid copolymer. Moreover, in the above ethylene copolymer (A), the amount of the ethylene unit is 50 to 95% by weight, preferably 70 to 85% by weight, and the unsaturated ester unit is 1 to 40% by weight, preferably 5 to 50% by weight. In an amount of 25% by weight, unsaturated carboxylic acid units are included in an amount of 1 to 20% by weight, preferably 2 to 12% by weight. However, in the case where the ethylene copolymer (A) is a mixture, the amount of each component is such that when the total amount of all the component units of the copolymer contained in the mixture (i) is 100% by weight. It is a value. When the ethylene copolymer (A) contains an ethylene unit in an amount of less than 50% by weight, mechanical properties of the obtained thermoplastic resin composition may deteriorate and blocking may increase. Further, when the unsaturated ester unit and the unsaturated carboxylic acid unit are contained in the respective amounts as described above, such an ethylene copolymer (A) contains ethylene.
A thermoplastic resin composition having excellent compatibility with the unsaturated ester / carbon monoxide copolymer (B) and having excellent flexibility, transparency, mechanical strength, and tensile properties can be obtained.

When the above ethylene copolymer (A) is the mixture (i), the ethylene / unsaturated ester / unsaturated carboxylic acid copolymer is 100 weight% of the total amount of the copolymer in the mixture (i). %, And it is preferable that the content is 60% by weight or more.

As described above, the ethylene copolymer (A) includes (i) an ethylene / unsaturated ester / unsaturated carboxylic acid copolymer, an ethylene / unsaturated ester copolymer and an ethylene / unsaturated carboxylic acid copolymer. It is a mixture of two or more copolymers selected from the group consisting of polymers, or (i
i) It is an ethylene / unsaturated ester / unsaturated carboxylic acid copolymer, and the unsaturated ester unit constituting such various copolymers is derived from unsaturated ester such as unsaturated carboxylic acid ester or vinyl ester. To be done.

As the unsaturated carboxylic acid ester,
Specifically, for example, methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate,
Examples thereof include lower alkyl esters of unsaturated carboxylic acids having about 1 to 10 carbon atoms, such as methyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, diethyl maleate and the like.

Specific examples of the vinyl ester include vinyl acetate and vinyl propionate. Among these unsaturated esters, acrylic acid esters or methacrylic acid esters are preferably used. These unsaturated esters can be used alone or in combination of two or more. When such an ethylene copolymer (A) is a mixture, the total amount of unsaturated ester units in the copolymer (A) is 100% by weight,
The total amount of units derived from acrylic acid ester and / or methacrylic acid ester is preferably 80% by weight or more.

The unsaturated carboxylic acid unit is specifically derived from, for example, acrylic acid, methacrylic acid, monomethyl maleate, monoethyl maleate, maleic anhydride or the like, and methacrylic acid or acrylic acid is preferably used.

The ethylene / unsaturated ester / unsaturated carboxylic acid copolymer (a) consisting of such various component units has an ethylene unit content of 50 to 95% by weight, preferably 7%.
0-85% by weight, unsaturated ester units 1-40% by weight, preferably 5-25% by weight unsaturated carboxylic acid units 1-20% by weight, preferably 2-12% by weight. Specifically, for example, ethylene / methyl acrylate / acrylic acid copolymer, ethylene / ethyl acrylate / acrylic acid copolymer, ethylene / isobutyl acrylate / acrylic acid copolymer, ethylene / methyl methacrylate / Acrylic acid copolymer, ethylene / methyl acrylate / methacrylic acid copolymer, ethylene / ethyl acrylate / methacrylic acid copolymer, ethylene / isobutyl acrylate / methacrylic acid copolymer, ethylene / n-butyl acrylate / Methacrylic acid copolymer, ethylene / methyl methacrylate / methacrylic acid copolymer, ethylene / isobutyl methacrylate / Methacrylic acid copolymer, ethylene / methyl acrylate / monoethyl maleate copolymer, and the like of ethylene / ethyl acrylate / maleic anhydride copolymer.

Ethylene / unsaturated ester copolymer (II)
Is a copolymer of 70 to 95% by weight of ethylene units, preferably 75 to 90% by weight, and 5 to 30% by weight of unsaturated ester units, preferably 10 to 25% by weight. , For example, ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer, ethylene / isobutyl acrylate copolymer, ethylene / n-butyl acrylate copolymer, ethylene / methyl methacrylate copolymer, Examples thereof include ethylene / vinyl acetate copolymer.

The ethylene / unsaturated carboxylic acid copolymer (c) has an ethylene unit content of 75 to 96% by weight, preferably 80 to 94% by weight, and an unsaturated carboxylic acid unit content of 4%.
-25% by weight, preferably 6-20% by weight, and specific examples thereof include ethylene / acrylic acid copolymers and ethylene / methacrylic acid copolymers.

In the present invention, as the ethylene / unsaturated ester / unsaturated carboxylic acid copolymer, for example, a copolymer in which the unsaturated ester unit is isobutyl acrylate,
Two or more kinds of ethylene / unsaturated ester / unsaturated carboxylic acid copolymers having different component unit compositions may be used, for example, a copolymer in which the unsaturated ester unit is n-butyl methacrylate is used together, or a component Two or more kinds of ethylene / unsaturated ester / unsaturated carboxylic acid copolymers having different unit amounts may be used in combination. The same applies to the ethylene / unsaturated ester copolymer (b) or the ethylene / unsaturated carboxylic acid copolymer (c).

The melt flow rate of such an ethylene copolymer (A) (MFR, according to JIS K 7210, 190
C., measured with a load of 2160 g) is usually 0.1 to 10
It is desirable that the amount is 0 g / 10 minutes, preferably 1 to 50 g / 10 minutes. When the ethylene copolymer (A) is the mixture (i), the melt flow rate (MFR) is
The value of the mixture is shown.

[ Ethylene, unsaturated ester, carbon monoxide
Copolymer (B) ] The unsaturated ester unit constituting the ethylene / unsaturated ester / carbon monoxide copolymer (B) is the same as the unsaturated ester unit constituting the ethylene copolymer (A). There are things. Among these, component units derived from acrylic acid ester, methacrylic acid ester or vinyl acetate are preferable, and component units derived from vinyl acetate are most preferable.

In the ethylene / unsaturated ester / carbon monoxide copolymer (B), the ethylene component unit is 50 to 8
Included in an amount of 9% by weight, preferably 55-80% by weight,
10 to 45% by weight of unsaturated ester units, preferably 1
Included in an amount of 5-40% by weight and containing 1-2 carbon monoxide units.
It is desirable that it is contained in an amount of 0% by weight, preferably 2 to 15% by weight.

In the ethylene / unsaturated ester / carbon monoxide copolymer (B), when the content of the unsaturated ester unit is less than 10% by weight, the copolymer (B) and the ethylene copolymer are added. The affinity with the polymer (A) may decrease, and the transparency and flexibility of the resulting thermoplastic resin composition may decrease. Further, when the content of the carbon monoxide unit is in the above range, a thermoplastic resin composition excellent in high-frequency welder property can be obtained. However, when the content exceeds the above range, the ethylene copolymer (A ), The affinity with may decrease.

Specific examples of the ethylene / unsaturated ester / carbon monoxide copolymer (B) include:
Ethylene / methyl acrylate / carbon monoxide copolymer, ethylene / ethyl acrylate / carbon monoxide copolymer, ethylene / isobutyl acrylate / carbon monoxide copolymer, ethylene / isooctyl acrylate / carbon monoxide copolymer Examples thereof include polymer, ethylene / methyl methacrylate / carbon monoxide copolymer, ethylene / n-butyl methacrylate / carbon monoxide copolymer, ethylene / vinyl acetate / carbon monoxide copolymer and the like.

The melt flow rate (MF) of such an ethylene / unsaturated ester / carbon monoxide copolymer (B)
R, JIS K 7210, 190 ° C., 2160 g load) is usually 0.1 to 100 g / 10 minutes, preferably 1 to 50 g / 10 minutes.

Ethylene / unsaturated ester /
Various copolymers constituting the carbon monoxide copolymer (B) or the ethylene copolymer (A), that is, ethylene / unsaturated ester / unsaturated carboxylic acid copolymer, ethylene /
The unsaturated ester copolymer and the ethylene / unsaturated carboxylic acid copolymer can be easily obtained by radically copolymerizing each copolymer-forming monomer under high temperature and high pressure. A conventionally known method may be used as a method for producing these copolymers.

[ Thermoplastic resin composition ] The thermoplastic resin composition according to the present invention comprising the ethylene copolymer (A) and the ethylene / unsaturated ester / carbon monoxide copolymer (B) as described above , Ethylene copolymer (A) 50 to 99
50 parts by weight, preferably 60 to 95 parts by weight, of the ethylene / unsaturated ester / carbon monoxide copolymer (B) is 50 parts by weight.
-1 part by weight, preferably 40-5 parts by weight. Particularly, 30 to 5 parts by weight of the copolymer (B) is added to 70 to 95 parts by weight of the copolymer (A) [copolymer (A)].
And 100% by weight of the copolymer (B). ] The thermoplastic resin composition contained in the amount of] is excellent in transparency.

The thermoplastic resin composition according to the present invention comprises an ethylene copolymer (A) and an ethylene / unsaturated ester / carbon monoxide copolymer (B). ) And the copolymer (B), the unsaturated carboxylic acid unit is 1 to 100 parts by weight based on the total of 100 parts by weight of all the component units such as ethylene unit, unsaturated carboxylic acid unit, unsaturated ester unit and carbon monoxide unit. 5 parts by weight, the unsaturated ester unit is contained in an amount of 15 to 30 parts by weight, and the carbon monoxide unit is contained in an amount of 1 to 5 parts by weight, and the copolymer (A) and the copolymer. It is desirable to use (B).

The thermoplastic resin composition of the present invention includes an antioxidant, a heat stabilizer, a light resistance stabilizer, an ultraviolet absorber, an antistatic agent, an antifogging agent, a lubricant, an antiblocking agent, a flame retardant, a pigment and a dye. , An inorganic filler, etc. may be contained. Further, a thermoplastic resin other than the above may be contained.

[0031]

According to the present invention, flexibility, mechanical strength,
Provided is a thermoplastic resin composition having excellent high frequency welder characteristics. Such a thermoplastic resin composition can be processed into molded articles of various shapes by various molding methods such as extrusion molding, injection molding, hollow molding, compression molding and vacuum molding. Since the thermoplastic resin composition according to the present invention has the above-mentioned excellent properties, it can be suitably used as, for example, a film, a sheet, a tube or the like instead of the soft PVC. More specifically, it can be used for various purposes such as a small case, a file, a cover for covering, a rain cover and a clear holder.

[0032]

EXAMPLES The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples. In the following Examples and Comparative Examples, the amounts of copolymerization components such as ethylene and isobutyl acrylate are shown in “parts by weight” unless otherwise specified.

[0033]

Examples 1 to 3 Films made of the thermoplastic resin composition according to the present invention were prepared by the following methods, and their physical properties were evaluated by the following methods. (1) Ethylene / unsaturated ester / unsaturated carboxylic acid
Polymer (A) and ethylene / unsaturated ester / carbon monoxide
Preparation of Film Made of Composition Comprising Copolymer (B) Ethylene (E) / isobutyl acrylate (iBA) / methacrylic acid (MAA) copolymer [A] (E / iBA / MAA = 80 /
15/5, MFR = 10g / 10min) and ethylene (E)
・ Vinyl acetate (VA) / carbon monoxide (CO) copolymer [B] (E
/ VA / CO = 66/24/10; MFR = 35 g / 1
0 minutes) and a twin screw extruder (screw diameter 33m
m, L / D = 32) and mixed and supplied at a predetermined composition ratio shown in Table 1 below, resin temperature 170 ° C., extrusion rate 12 kg
The mixture was kneaded and extruded under the condition of / hour and molded into pellets. Then, using an inflation molding machine, a single layer film having a thickness of 50 μm and a width of 220 mm was prepared from the pelletized material. The physical properties of the monolayer film thus obtained were evaluated for the following items.

The results are shown in Table 1 and FIGS. [Physical property evaluation items of single-layer film] (2) Welder seal characteristics High frequency welder KV-3000TA manufactured by Seidensha Electronics Co., Ltd.
Was used to evaluate the sealing property between the films.

In the evaluation of the sealing property of this single layer film, the optimum level of the welder seal was examined by adjusting the tuning level of the high frequency welder and the oscillation time. (3) MFR JIS K 7210, test temperature 190 ℃, load 2160
It was measured in g. (4) Optical property (Haze) Based on JIS K 6714, it was measured at a test temperature of 23 ° C. (5) Optical property (Gloss) Based on JIS Z 8741, it measured at the test temperature of 23 degreeC. (6) Optical property (Trans) According to ASTM D 1746, it was measured at a test temperature of 23 ° C. (7) Film Impact Film impact was measured using a film impact tester manufactured by Toyo Seiki. That is, a 0.5 inch diameter hemispherical cone that was previously attached to the tip of the film impact tester was abutted to the center of a horizontally stretched circular sample (single layer film) with a certain area, and the force when the sample broke Was measured. (8) Tear strength Measured at a test temperature of 23 ° C. according to JIS K 6732. (9) Tensile test Measured at a test temperature of 23 ° C. according to JIS K 7113.

[0036]

Comparative Example 1 A film was prepared in the same manner as in Example 1 except that the composition of the thermoplastic resin composition was changed as shown in Table 1, and its physical properties were evaluated.

The results are shown in Table 1.

[0038]

[Table 1]

According to Table 1, the welder characteristics are improved in the example of the present invention as compared with the comparative example 1. Particularly, in Example 3 in which the copolymer [B] was used in an amount of 30% by weight, the tuning level was 75 and the oscillation time was 3 seconds. Such a welder characteristic value was used for flexible containers at present. Entrainment level 7 for ethylene-vinyl acetate copolymer (EVA) with 19% vinyl (VA) content
8, the oscillation time is at the same level as 3 seconds, and it can be seen that the welder characteristics are significantly improved as compared with Comparative Example 1.

Further, referring to the initial strain-stress curves shown in FIGS. 1 and 2, the copolymer [A] shown in Comparative Example 1 has an initial strain-stress characteristic (behavior) similar to that of polyvinyl chloride (PVC). However, in all of Examples 1 to 3, Comparative Example 1
Shows the same initial strain-stress characteristic, and the film made of the thermoplastic resin composition according to the present invention exhibits an initial strain-stress characteristic similar to that of polyvinyl chloride (PVC).

[Brief description of drawings]

FIG. 1 shows the stress (kgf / c) for the thermoplastic resin composition films shown in Examples 1 to 3 and Comparative Example 1.
The result of measuring the relationship between m ² ) and elongation (%) in the lateral direction of the film is shown.

FIG. 2 shows the stress (kgf / c) for the thermoplastic resin composition films shown in Examples 1 to 3 and Comparative Example 1.
The result of measuring the relationship between m ² ) and elongation (%) in the longitudinal direction of the film is shown.

[Explanation of symbols]

1 and 2, the horizontal axis represents the film elongation (%).
The vertical axis represents the stress applied to the film (kgf / c
m ² ) is shown.

Claims (2)

(57) [Claims] 1. An ethylene copolymer (A) in an amount of 50 to 99 parts by weight, and an ethylene / unsaturated ester / carbon monoxide copolymer (B).
A resin composition comprising 50 to 1 part by weight [the total amount of (A) and (B) is 100 parts by weight], wherein the ethylene copolymer (A) is (i) ethylene unsaturated. It is a mixture of two or more kinds selected from the group consisting of an ester / unsaturated carboxylic acid copolymer, an ethylene / unsaturated ester copolymer and an ethylene / unsaturated carboxylic acid copolymer, or (ii) ethylene. Any of unsaturated ester / unsaturated carboxylic acid copolymers, wherein the ethylene copolymer (A) contains 50 to 50 ethylene units.
A thermoplastic resin composition, characterized in that it contains 95% by weight of unsaturated ester units in an amount of 1-40% by weight and unsaturated carboxylic acid units in an amount of 1-20% by weight. 2. A film comprising the thermoplastic resin composition according to claim 1.