JP3334975B2 - Thermoplastic resin composition and film comprising the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin composition comprising a specific thermoplastic polyurethane and a specific ethylene-vinyl acetate copolymer, and a film comprising the resin composition. The thermoplastic resin composition of the present invention has elastic recovery properties,
Excellent strength and flexibility. The film of the present invention effectively exhibits the features of the resin composition and is useful as a stretchable film.

[0002]

2. Description of the Related Art Thermoplastic polyurethane has elastic recovery,
Although it has excellent performance in strength and flexibility, it is a relatively expensive resin. On the other hand, polyolefin resins such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer and ethylene-methyl acrylate copolymer are less expensive than thermoplastic polyurethane. Therefore, blending of a polyolefin resin with a thermoplastic polyurethane has been attempted for the purpose of obtaining a thermoplastic resin material having excellent properties of the thermoplastic polyurethane at a low cost. However, the polyolefin resin and the thermoplastic polyurethane are incompatible, and when both are simply blended, the dispersion state is not good. For that reason, when a resin composition of a thermoplastic polyurethane and a polyolefin-based resin is used for film forming, there is a problem that film formation stability is low and it is difficult to make the film thinner, and also in the obtained film. There is a problem that performance such as elastic recovery, strength, and flexibility is insufficient.

[0003]

SUMMARY OF THE INVENTION One object of the present invention is to provide a thermoplastic resin comprising a thermoplastic polyurethane and a polyolefin resin and having the same excellent elastic recovery, strength and flexibility as thermoplastic polyurethane. It is to provide a resin composition. Another object of the present invention is to provide a film comprising a thermoplastic polyurethane and a polyolefin resin and having excellent elastic recovery, strength and flexibility.

[0004]

According to the present invention, one of the above objects is to provide a thermoplastic polyurethane and an ethylene-vinyl acetate copolymer having a weight ratio of thermoplastic polyurethane / ethylene-vinyl acetate copolymer. Is 60 / 40-9
In a thermoplastic resin composition in the range of 0/10,
The thermoplastic polyurethane has a number average molecular weight of 100 having 2-methyl-1,3-propanediol as a diol component.
The hardness (JI) obtained by reacting a polyester diol of 0 to 6000, an organic diisocyanate and a chain extender.
SA) a polyurethane of 85 or less;
The vinyl acetate copolymer has a vinyl acetate component content of 5 to 3
This is achieved by providing a thermoplastic resin composition characterized by being an ethylene-vinyl acetate copolymer having a melt flow rate (190 ° C., load 2160 g) of 20% by weight or less. According to the present invention, the other objects are attained by providing a film comprising the thermoplastic resin composition.

A thermoplastic polyurethane is generally obtained by reacting a polymer diol, an organic diisocyanate and a chain extender. In the present invention, 2-methyl-1,3-propanediol is used as the polymer diol as a diol component. It is important to use a polyester diol having a number average molecular weight of 1,000 to 6,000.

The polyester diol used in the present invention is:
2-methyl-1, as at least a part of the diol component,
Has 3-propanediol. 2 as diol component
When a polyester diol having no -methyl-1,3-propanediol is used, the obtained thermoplastic polyurethane is mixed with the above-mentioned ethylene-vinyl acetate copolymer to form a resin composition. The composition is not preferable because the elastic recovery property and strength are insufficient and the flexibility is also poor, probably because the dispersed particle size of the ethylene-vinyl acetate copolymer is large. In general, as the proportion of 2-methyl-1,3-propanediol in the diol component increases, the elastic recovery, strength, and flexibility of the obtained resin composition tend to be improved. % Or more is preferably 2-methyl-1,3-propanediol, and more preferably 50 mol% or more is 2-methyl-1,3-propanediol. As described above, as the diol component, 2
-Methyl-1,3-propanediol may be used in combination with another diol. Diols that can be used in combination with 2-methyl-1,3-propanediol include ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, neopentyl glycol, 1,6- Hexanediol, 2-methyl-1,8-
Examples thereof include saturated aliphatic diols such as octane diol and 1,9-nonane diol, and two or more of these diols may be used. Among them, ethylene glycol and / or 1,4-butanediol are preferred because the effects derived from 2-methyl-1,3-propanediol are not easily lost. Furthermore, as long as the flexibility of the obtained thermoplastic resin composition is not reduced,
A trifunctional or higher polyol may be used in combination. The use amount of the trifunctional or higher polyol is preferably 5 mol% or less based on all diol components.

The dicarboxylic acid component constituting the polyester diol together with the diol component includes glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, 2-methylsuccinic acid and 2-methyladipin. Dicarboxylic acids such as acids, aliphatic dicarboxylic acids such as 3-methyladipic acid, 3-methylpentanedioic acid and 2-methyloctanedioic acid can be used.

The number average molecular weight of the polyester diol used in the present invention is from 1,000 to 6,000. When the number average molecular weight is less than 1000, the resulting thermoplastic polyurethane has insufficient flexibility at low temperatures and also has poor heat resistance, so that the resin composition has insufficient properties such as flexibility.
On the other hand, if the number average molecular weight exceeds 6000, the resulting thermoplastic resin composition tends to have an increased melt viscosity during extrusion molding, resulting in insufficient moldability.
Not preferred.

The method for producing the polyester diol used in the present invention is not particularly limited. Therefore, the polyester diol can be produced by a method similar to the known method used in producing polyesters such as polyethylene terephthalate and polybutylene terephthalate, that is, transesterification or direct esterification followed by a melt polycondensation reaction. . In the polycondensation reaction, a titanium-based or tin-based polycondensation catalyst may be used. However, when a titanium-based polycondensation catalyst is used, it is preferable to deactivate the polycondensation catalyst in the obtained polyester diol after the polycondensation reaction. By deactivating the polycondensation catalyst, the resulting thermoplastic polyurethane is suppressed from decreasing in the blockability of the hard segment and the soft segment that gradually occur while the molten polyurethane stays at a high temperature.
Also in the film, various properties such as heat resistance and elastic recovery originally possessed by the thermoplastic polyurethane are effectively exhibited. As a method of deactivating the polycondensation catalyst in the polyester diol, there is a contact treatment with water. For example, water of 1 to 4% by weight is added to
A method of stirring at 50 ° C, a method of stirring at 100 to 150 ° C while passing steam through the polyester diol, and the like can be adopted. The polycondensation catalyst can also be deactivated by adding a phosphorus compound which is generally used for deactivating the polyester catalyst.

In the present invention, it is preferable to use the above-mentioned polyester diol alone as a polymer diol, but if desired, a small amount (usually 30% by weight or less of the polymer diol) may be used as other polymer diol. A diol (for example, a polycarbonate diol, a polyether diol, or a polyester diol other than the above-described polyester diol) may be used in combination.

The organic diisocyanate used in the present invention includes 4,4'-diphenylmethane diisocyanate, p-phenylene diisocyanate, tolylene diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4,4 '
Organic diisocyanates known to be generally usable in polyurethane production, such as -dicyclohexylmethane diisocyanate. Among these,
4,4'-diphenylmethane diisocyanate is preferred.

In the present invention, as the chain extender,
Chain extenders known to be commonly used in polyurethane production can be used. As the chain extender, a low molecular weight compound having a molecular weight of 300 or less and containing at least two hydrogen atoms capable of reacting with isocyanate in the molecule is preferable. Examples include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6
-Hexanediol, 1,4-bis (2-hydroxyethoxy) benzene, 1,4-cyclohexanediol,
And diols such as bis (β-hydroxyethyl) terephthalate and xylylene glycol. These chain extenders are used alone or as a mixture of two or more. Among these chain extenders, 1,4-butanediol is particularly preferred.

In the production of polyurethane, isocyanate groups are contained in an amount of 0.9 to 1.3 mol per mol of active hydrogen atoms, preferably 0.9 mol to 1.3 mol, based on the total amount of active hydrogen atoms contained in the polymer diol and the chain extender. Is 0.95
It is preferred to use the organic diisocyanate in such a proportion as to give 1.30 mol.

With respect to the method for producing a thermoplastic polyurethane by reacting a polymer diol, an organic diisocyanate and a chain extender, known urethanization techniques such as melt polymerization and solution polymerization can be employed. Among them, it is preferable to carry out melt polymerization substantially in the absence of a solvent, and particularly preferable is a continuous melt polymerization method using a multi-screw extruder. Although the melt polymerization temperature is not particularly limited,
The temperature is preferably from 180 ° C to 260 ° C.

In the course of or after the polymerization, a coloring agent,
Various additives such as flame retardants, ultraviolet absorbers, antioxidants, hydrolysis resistance improvers, and fungicides; various fibers such as glass fibers and polyester fibers; inorganic substances such as mica and talc; various coupling agents. It may be appropriately selected and added.

It is important that the thermoplastic polyurethane used in the present invention has a hardness (JIS-A) of 85 or less. When the hardness exceeds 85, the flexibility of the obtained thermoplastic resin composition becomes insufficient, which is not preferable.

The ethylene-vinyl acetate copolymer used in the present invention contains 5 to 30% by weight of a vinyl acetate component, and has a melt flow rate (190 ° C., load 2160).
g) is 20 or less. When the content of the vinyl acetate component is less than 5% by weight, the elastic recovery, strength and the like may be reduced, probably because the particle size of the ethylene-vinyl acetate copolymer particles dispersed in the thermoplastic resin composition is large. Is not preferred. On the other hand, when the content of the vinyl acetate component exceeds 30% by weight, disadvantages such as an increase in the tackiness of a film formed from the thermoplastic resin composition occur, which is not preferable. The melt flow rate (190 ° C., load 2160
If g) exceeds 20, the elastic recovery property, strength and flexibility may decrease, possibly due to the poor dispersion state of the ethylene-vinyl acetate copolymer in the thermoplastic resin composition, and the film formation may become difficult. Become. The melt flow rate of the ethylene-vinyl acetate copolymer is preferably 10 or less, and more preferably 5 or less, since the elastic recovery property, strength, flexibility, and film-forming property of the obtained thermoplastic resin composition are particularly good. Is more preferable. The lower limit of the melt flow rate is not particularly limited, but is preferably 0.1 or more.

In the thermoplastic resin composition of the present invention,
The mixing ratio between the thermoplastic polyurethane having the specific structure and the specific ethylene-vinyl acetate copolymer is 60/40 to 90/10 by weight of the thermoplastic polyurethane / ethylene-vinyl acetate copolymer. It is important to be within range. When the amount of the thermoplastic polyurethane is less than 60 parts by weight per 40 parts by weight of the ethylene-vinyl acetate copolymer, the properties of elastic recovery, strength, heat resistance, and the like are reduced as compared with the case of the thermoplastic polyurethane alone. Because it ’s big
Not preferred. On the other hand, when the thermoplastic polyurethane exceeds 90 parts by weight with respect to 10 parts by weight of the ethylene-vinyl acetate copolymer, the purpose of the present invention is not met from an economic viewpoint.

The thermoplastic resin composition of the present invention can be produced by a usual polymer blending method except that the above-mentioned thermoplastic polyurethane and ethylene-vinyl acetate copolymer are used. For example, after the thermoplastic polyurethane and the ethylene-vinyl acetate copolymer are premixed at a predetermined ratio using a vertical or horizontal mixer as generally used for mixing a resin material, the mixture is then uniaxially mixed. Alternatively, the thermoplastic resin composition of the present invention is produced by melt kneading in a batch or continuous manner with heating using a twin-screw extruder, mixing roll, Banbury mixer, or the like. During mixing, light stabilizers, stabilizers for improving heat resistance and the like, plasticizers, lubricants such as aliphatic amides, fillers, antistatic agents, additives such as pigments, do not impair the effects of the present invention. It may be added in an amount.

As a method for producing a film from the thermoplastic resin composition of the present invention, a film forming method by ordinary melt extrusion molding such as inflation molding and T-die molding can be employed.

The above-mentioned specific thermoplastic polyurethane and ethylene-vinyl acetate copolymer constituting the thermoplastic resin composition of the present invention can be mixed with ethylene-vinyl acetate in a matrix of thermoplastic polyurethane simply by melt-mixing. Fine particles of the copolymer can be uniformly dispersed. Therefore,
When a film is produced from the thermoplastic resin composition of the present invention, the film-forming stability is good and the film can be made thinner. The obtained film is excellent in elastic recovery, strength, flexibility and the like.

[0022]

The present invention will be described below in detail with reference to examples. In the examples, the elastic recovery rate, strength and flexibility (feel) were evaluated by the following methods.

[Elastic recovery rate] A test piece prepared from a 50-μm-thick film formed using a T-die under the conditions of a temperature of 23 ° C. and a humidity of 65% RH was subjected to a pulling speed of 200%.
mm / min. After 200% elongation, the stress was removed by holding for 2 minutes, and the return after 10 minutes was measured.
Based on the test results, the elastic recovery was calculated according to the following equation.

[0024]

(Equation 1)

[Strength] Film thickness 50 formed using a T-die
For a test piece prepared from a μm film, a tensile speed of 200 mm / min. The strength was measured by performing a tensile test under the conditions of a temperature of 23 ° C. and a humidity of 65% RH.

[Flexibility (Hand)] The flexibility (hand) of a film having a thickness of 50 μm formed using a T-die was evaluated according to the criterion shown in Table 1 below by the feel of the hand.

[0027]

[Table 1]

In the examples, the compounds are represented by the abbreviations shown in Table 2 below.

[0029]

[Table 2]

Reference Example 1 (Production of Polyester Diol A) MPrG (108 kg) and AD (146 kg) were charged into a reactor, and nitrogen gas was passed through the system at normal pressure to about 220 kg.
At a temperature of ° C., the esterification reaction was carried out while distilling off generated water out of the system. When the acid value of the polyester became 30 or less, tetraisopropyl titanate was added, and 200
The polycondensation reaction was started while reducing the pressure to １００100 mmHg. When the acid value reached 1.0, the degree of vacuum was gradually increased by a vacuum pump to complete the reaction. As a result, 205 kg of a polyester diol having a number average molecular weight of 2,000 (referred to as “polyester diol A”) was obtained.

Reference Example 2 (Production of Polyester Diol B) MPrG and AD were charged into a reactor and subjected to an esterification reaction and a polycondensation reaction in the same manner as in Reference Example 1 to obtain a number average molecular weight of 2
000 polyester diols were obtained. The obtained polyester diol was heated to 100 ° C., 3% by weight of water was added, and the mixture was stirred at the same temperature for 2 hours to deactivate the titanium catalyst. Then, water was distilled off under reduced pressure. A polyester diol in which the titanium catalyst was deactivated by this treatment (this is called "polyester diol B") was obtained.

Reference Examples 3 to 6 (Production of Polyester Diols C, D, E and F) The diols used were mixed diols of MPrG and ED (Reference Example 3) and mixed diols of MPrG, ED and BD (Reference An esterification reaction and a polycondensation reaction were carried out in the same manner as in Reference Example 1 except for changing to Example 4) or BD (Reference Examples 5 and 6) to obtain a polyesterdiol having a number average molecular weight of 2,000. Further, for some polyester diols, the titanium catalyst was deactivated in the same manner as in Reference Example 2 (Reference Examples 3, 4, and 6). In this way,
The polyester polyols shown in Table 3 below (these are referred to as polyester diols C, D, E and F, respectively) were obtained.

[0033]

[Table 3]

Reference Example 7 {Production of Polyurethane (Polyester Diol A / MDI / BD)} The polyester diols A, MDI and BD obtained in Reference Example 1 were prepared by mixing the polyester diol A / MDI / BD with a molar ratio of 1 / 3/2, the total amount of these is 300
g / min, with a metering pump, a twin screw extruder (30 mmφ; L
/ D = 36; cylinder temperature: about 200 per block
(Set within the range of about 250 ° C. to about 250 ° C.) to carry out a continuous melt polymerization reaction. The resulting thermoplastic polyurethane melt was continuously extruded into water in strands, then cut with a pelletizer and formed into pellets. The pellet was dehumidified and dried at 80 ° C. for 20 hours. Thus, a thermoplastic polyurethane having a hardness (JIS-A) of 75 was obtained.

[Reference Example 8] {Production of Polyurethane (Polyester Diol B / MDI / BD)} The polyester diol B, MDI and BD obtained in Reference Example 2 were used in a molar ratio of polyester diol B / MDI / BD of 1 A thermoplastic polyurethane having a hardness (JIS-A) of 75 was obtained by performing a continuous melt polymerization reaction, pelletizing, and dehumidifying and drying in the same manner as in Reference Example 7, except that it was used at a ratio of / 3/2.

[Reference Example 9] {Production of Polyurethane (Polyester Diol C / MDI / BD)} The polyester diol C, MDI and BD obtained in Reference Example 3 were prepared by mixing the polyester diol C / MDI / BD with a molar ratio of 1 A thermoplastic polyurethane having a hardness (JIS-A) of 78 was obtained by performing a continuous melt polymerization reaction, pelletizing, and dehumidifying and drying in the same manner as in Reference Example 7, except that it was used at a ratio of / 3/2.

Reference Example 10 {Production of Polyurethane (Polyester Diol D / MDI / BD)} The polyester diols D, MDI and BD obtained in Reference Example 4 were prepared by mixing the polyester diol D / MDI / BD with a molar ratio of 1 A thermoplastic polyurethane having a hardness (JIS-A) of 79 was obtained by performing a continuous melt polymerization reaction, pelletizing, and dehumidifying and drying in the same manner as in Reference Example 7, except that it was used at a ratio of / 3/2.

[Reference Example 11] {Production of Polyurethane (Polyester Diol E / MDI / BD)} The polyester diol E, MDI and BD obtained in Reference Example 5 were used in a polyester diol E / MDI / BD molar ratio of 1 A thermoplastic polyurethane having a hardness (JIS-A) of 82 was obtained by performing continuous melt polymerization reaction, pelletizing, and dehumidifying and drying in the same manner as in Reference Example 7, except that the mixture was used at a ratio of / 3/2.

[Reference Example 12] {Production of Polyurethane (Polyester Diol F / MDI / BD)} The polyester diol F, MDI and BD obtained in Reference Example 6 were used in a polyester diol F / MDI / BD having a molar ratio of 1 A thermoplastic polyurethane having a hardness (JIS-A) of 82 was obtained by performing continuous melt polymerization reaction, pelletizing, and dehumidifying and drying in the same manner as in Reference Example 7, except that the mixture was used at a ratio of / 3/2.

Example 1 A 70% by weight of the thermoplastic polyurethane obtained in Reference Example 7 had a VAc content of 25% by weight.
Melt flow rate (hereinafter abbreviated as MFR) (190 ° C,
30% by weight of EVAc with a load of 2160 g)
Extruder (cylinder temperature and die temperature: 205
C), and the resulting thermoplastic resin composition is melted and kneaded at T.
The film was extruded from a die and wound up through a cooling roll to obtain a film having a thickness of 50 μm. In addition, the film forming property was stable. After leaving the obtained film at 25 ° C. for 7 days, the elastic recovery, strength and flexibility were evaluated. The evaluation results are shown in Table 4 below.

[Examples 2 to 4] VAc was added to 70% by weight of the thermoplastic polyurethane obtained in Reference Examples 8 to 10, respectively.
Content 25% by weight, MFR (190 ° C., load 2160
g) 30% by weight of EVAc of 2 were kneaded and formed into a film in the same manner as in Example 1 to obtain a film composed of a thermoplastic resin composition. After leaving the film in the same manner as in Example 1, the film was evaluated and the results shown in Table 4 were obtained. In each case, the film-forming properties were stable.

Comparative Example 1 A 50% by weight of the thermoplastic polyurethane obtained in Reference Example 8 was added to a content of 25% by weight of VAc.
EVAc50 of MFR (190 ° C, load 2160g) 2
The mixture was kneaded in the same manner as in Example 1 to form a film, and a film made of the thermoplastic resin composition was obtained. After leaving the film in the same manner as in Example 1, the film was evaluated and the results shown in Table 4 were obtained. In addition, the film forming property was unstable.

Comparative Example 2 A 70% by weight of the thermoplastic polyurethane obtained in Reference Example 8 had a VAc content of 33% by weight,
EVAc3 with MFR (190 ° C, load 2160g) 30
0 wt% was kneaded and formed into a film in the same manner as in Example 1 to obtain a film made of a thermoplastic resin composition. After leaving the film in the same manner as in Example 1, the film was evaluated and the results shown in Table 4 were obtained. In addition, the film forming property was unstable.

[Comparative Examples 3 and 4] 70% by weight of the thermoplastic polyurethane obtained in Reference Example 11 or 12, 25% by weight of VAc, MFR (190 ° C., load 2160 g)
2 and 30% by weight of EVAc were kneaded in the same manner as in Example 1,
By forming the film, a film made of the thermoplastic resin composition was obtained. After leaving the film in the same manner as in Example 1, the film was evaluated and the results shown in Table 4 were obtained. In addition, the film forming property was unstable.

[0045]

[Table 4]

From Table 4 above, it can be seen that Examples 1 to 4 according to the present invention were used.
The thermoplastic resin composition of the present invention provides a film having excellent elastic recovery, strength and flexibility, and in particular, uses a thermoplastic polyurethane produced using a polyester diol subjected to a deactivation treatment of a polycondensation catalyst. In Examples 2 to 4, it can be seen that the elastic recovery and strength of the film are further improved. On the other hand, it can be seen that the thermoplastic resin compositions of Comparative Examples 1 to 4, which are different from the present invention, can only obtain films having poor elastic recovery, strength and flexibility.

[0047]

According to the present invention, there is provided a thermoplastic resin composition having excellent elastic recovery, strength and flexibility comparable to those of a thermoplastic polyurethane alone. The thermoplastic resin composition is inexpensive as compared to the thermoplastic polyurethane alone because the ethylene-vinyl acetate copolymer is blended with the thermoplastic polyurethane. The film of the present invention effectively exhibits the features of the thermoplastic resin composition,
Useful as a stretchable film.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI C08L 23:08) (56) References JP-A-7-133424 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 75/04-75/12 C08J 5/18 C08G 18/00-18/87

Claims (3)

(57) [Claims] A thermoplastic polyurethane and ethylene-
Made of vinyl acetate copolymer, thermoplastic polyurethane /
The weight ratio of the ethylene-vinyl acetate copolymer is 60 / 40-
In a thermoplastic resin composition falling within the range of 90/10, the thermoplastic polyurethane contains 2-methyl-1,3-
Number average molecular weight 1 with propanediol as the diol component
A polyurethane having a hardness (JIS-A) of 85 or less obtained by reacting a polyester diol, an organic diisocyanate and a chain extender of 000 to 6000, wherein the ethylene-vinyl acetate copolymer has a vinyl acetate component content of 5 -30% by weight, and the melt flow rate (190
A thermoplastic resin composition characterized by being an ethylene-vinyl acetate copolymer having a load of 2160 g at 20 ° C. or less. 2. The thermoplastic resin composition according to claim 1, wherein the polyester diol is a polyester diol obtained by deactivating a polycondensation catalyst after polycondensation. 3. A film comprising the thermoplastic resin composition according to claim 1 or 2.