JP3365669B2 - Resin composition - Google Patents

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention has good moldability, impact strength, flexibility and interlayer adhesion without impairing water solubility or water dispersibility (hereinafter collectively referred to as water solubility). The present invention relates to a polyvinyl alcohol resin composition whose properties are stable over time.

[0002]

2. Description of the Related Art Molded products of polyvinyl alcohol (hereinafter abbreviated as PVA) resin, such as films, are excellent in properties such as aroma retention, transparency, oil resistance, antistatic property, oxygen barrier property and heat retention property. Also, since it has hydrophilicity and water solubility, it can be used for applications that are not suitable for ordinary hydrophobic polymer films.

In particular, a molded product made of an oxyalkylene group-containing PVA has an advantage that it is excellent in flexibility as compared with a general molded product made of PVA, and is used for various purposes.

The following various foreign applications have been made regarding molded articles or molding methods using such oxyalkylene group-containing PVA. US Pat. No. 4,618,864
No. 8 and No. 4675360 disclose a copolymer of PVA and poly (alkyleneoxy) acrylate, and this copolymer can be injection-molded and extruded, It is also disclosed that the product has water solubility and flexibility.

Japanese Unexamined Patent Publication No. 59-1655408 discloses
A modified PVA in which a copolymer of an unsaturated monomer containing an oxyalkylene group and vinyl acetate is saponified is disclosed, and the publication also describes a molded product as an example of its use. JP-A-3-203932, which is related to the present applicant, discloses a method for melt-molding an oxyalkylene group-containing vinyl alcohol copolymer under substantially anhydrous conditions. The publication describes that molding is performed substantially without using a plasticizer, and extrusion molding or injection molding can be used as a molding method.

Further, Japanese Patent Application Laid-Open No. 4-298 related to the present applicant
Japanese Patent No. 535 discloses a method for producing an oxyalkylene group-containing PVA-based resin molded product having a 4 wt% aqueous solution viscosity at 20 ° C. of 7 centipoise or less and a methanol-soluble content of 5 wt% or less, The publication describes that it can be melt-molded by mixing with other thermoplastic resins such as polyolefins such as polyethylene and polypropylene, nylon, polyester, polyvinyl chloride, polystyrene and the like.

[0007]

A molded article made of PVA containing an oxyalkylene group exhibits excellent flexibility as described above, but it cannot be said that it has sufficient flexibility and impact strength at low temperature. However, polyhydric alcohols such as glycerin, polyethylene glycol and polypropylene glycol have been added as such treatment. However, such a polyhydric alcohol has a drawback that its mechanical properties such as flexibility and impact strength are initially good, but its properties are deteriorated with time. There is a problem that the adhesive strength and the like also decrease with time.

Further, by adding another thermoplastic resin as in the technique disclosed in Japanese Patent Laid-Open No. 4-298535, there is a problem that the water solubility is impaired, although some improvement effect on flexibility and the like is recognized. . That is, there is a strong demand for a resin composition that retains the water-soluble properties of the PVA-based resin and does not exhibit deterioration in mechanical properties such as flexibility and impact resistance over time.

[0009]

However, as a result of intensive investigations by the present inventors to solve such problems, the PVA resin (A) containing an oxyalkylene group has 3 or more hydroxyl groups and 3 carbon atoms. Contains above, and has a melting point of 50 ° C or above 3
Specific polyhydric alcohol compound (B) having a temperature of less than 00 ° C
By blending 1 to 50% by weight of the PVA resin, the mechanical properties such as flexibility and impact resistance of the PVA-based resin are maintained while maintaining the water solubility and other properties, and the properties thereof are not deteriorated with time. It was found that a PVA-based resin composition excellent in interlayer adhesion with other substrates was obtained, and the present invention was completed. Hereinafter, the present invention will be described in detail.

The PVA-based resin (A) containing an oxyalkylene group used in the present invention is typically a fatty acid vinyl ester, a polyoxyethylene (meth) allyl ether, or a polyoxyethylene (meth) allyl ether represented by the following general formula 1. A copolymer obtained by copolymerizing a polyoxyalkylene (meth) allyl ether such as oxypropylene (meth) allyl ether and a polyalkylene vinyl ether such as polyoxyethylene vinyl ether or polyoxypropylene vinyl ether represented by the following general formula 2 Obtained by saponifying the polymer. Among them, the PVA-based resin (A) containing an oxyalkylene group obtained by saponifying a vinyl acetate-based copolymer is most preferable.

The copolymerization ratio of polyoxyalkylene (meth) allyl ether or polyalkylene vinyl ether is 0.1 to 30 mol%, preferably 0.5 to 10 mol%.
Particularly preferably, it is 1 to 5 mol%, and if it is less than 0.1 mol%, there is a problem in terms of imparting flexibility, impact resistance, extrusion moldability, and the like, and further when a specific polyhydric alcohol is blended. However, there is a problem in that the stability of the shape of the molded product and the physical properties inherent to PVA are impaired when the amount exceeds 30 mol%. The average degree of condensation of the polyoxyalkylene group in the polyoxyalkylene (meth) allyl ether is 3 to 100, and if the average degree of condensation is less than 3, there is a problem in terms of imparting flexibility, and the average degree of condensation is more than 100. If the amount is too large, there is a problem in that the moldability is lowered, and so it is preferably 5 to 80, particularly preferably 8 to 50. The content ratio of the oxyalkylene group in the entire polyoxyalkylene group-containing polyvinyl alcohol is preferably 3 to 40% by weight. This indicates that the degree of localization-delocalization of oxyalkylene groups and the length of oxyalkylene groups in the copolymer have an optimum range. The average degree of condensation referred to here means n in the chemical formulas shown in Chemical Formulas 1 and 2 below.

[0012]

[Chemical 1] (However, R ⁰ , R ¹ , R ² , and R ³ represent hydrogen or an alkyl group.)

[Chemical 2] (However, R ¹ , R ² , and R ³ represent hydrogen or an alkyl group.)

The degree of saponification of the fatty acid vinyl ester unit in the PVA-based resin (A) containing an oxyalkylene group is 80 to 100 mol%, and when it is 80 mol% or less, PV
There is a problem in that the original physical properties of A are impaired, the moldability is deteriorated, etc., and 85 to 100 mol% is preferable. or,
MFI (melt flow index) at 210 ° C. under a load of 2160 g is 0.1 to 100 g / 10 minutes, preferably 0.3 to 100 g / 10 minutes, and more preferably 0.5.
-100 g / 10 min is suitable.

As copolymerization components other than polyoxyalkylene (meth) allyl ether, for example, olefins such as ethylene, propylene, isobutylene, α-dodecene, α-octadodecene, maleic anhydride, maleic acid monoester, maleic acid diester, Itaconic acid, itaconic acid monoester, fumaric acid, fumaric acid monoester,
Citraconic acid, ethylenically unsaturated dicarboxylic acid such as citraconic acid monoester or its ester, nitriles such as acrylonitrile and methacrylonitrile, polymerizable acid amides such as acrylamide and methacrylamide, vinylidene chloride, and halodenation of vinylidene fluoride. Vinylidene, vinyl halides such as vinyl chloride and vinyl fluoride, acrylic acid ester, methacrylic acid ester, vinyl ketone, N-vinylpyrrolidone and the like may be contained at about 30 mol% or less.

As a polymerization method for obtaining the oxyalkylene group-containing PVA resin (A), a solution polymerization method is usually adopted, and a suspension polymerization method, an emulsion polymerization method or the like can be adopted depending on circumstances. As the saponification reaction,
An alkali saponification method, an acid saponification method, etc. can be adopted.

The oxyalkylene group-containing PVA-based resin (A) is, in addition to the above, fatty acid vinyl ester, polyoxyethylene (meth) acrylate, polyoxypropylene (meth) acrylate, polyoxyethylene (meth).
Polyoxyalkylene allylamine such as acrylamide, polyoxypropylene (meth) acrylamide, polyoxyethylene (1- (meth) acrylamide-1,1-dimethylpropyl) ester, polyoxyethylene allylamine, polyoxypropylene allylamine, polyoxyethylene vinyl It can also be obtained by copolymerizing amine, polyoxyalkylene vinyl amine such as polyoxypropylene vinyl amine, and then saponifying. The PVA-based resin (A) containing an oxyalkylene group can be obtained by a reaction of alkylene oxide with PVA, or polymerization of fatty acid vinyl ester with polyoxyalkylene glycol, and subsequent saponification in addition to the above method.

The specific polyhydric alcohol compound (B) used in the present invention contains 3 or more hydroxyl groups, preferably 4-10, and 3 or more carbon atoms, preferably 4-10, and has a melting point. 50 ° C or more and less than 300 ° C, preferably 1
Those having a temperature of 00 to 200 ° C. are preferably used. Polyhydric alcohols that do not satisfy any of the above conditions, such as glycerin, polyethylene glycol, ethylene glycol, diethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, triethylene glycol, 1,
With 3-butanediol, 2,3-butanediol, etc.,
Sufficient materials cannot be obtained from the viewpoint of imparting temporal stability of mechanical properties to the PVA-based resin (A) containing an oxyalkylene group.

Specific examples of the polyhydric alcohol compound (B) used in the present invention include pentaerythritol, dipentaerythritol, 2-ethyl-2-hydroxymethyl-1,3-propanediol, mannitol and sorbitol. , Polyglycerin, fructose, glucose, arabinitol, talit, and the like, particularly preferably pentaerythritol, sorbitol, mannitol, and polyglycerin.

The proportion of the polyhydric alcohol compound (B) to the PVA resin (A) containing an oxyalkylene group in the present invention is 1 to 50% by weight, preferably 3%.
˜45% by weight, particularly preferably 5-40. When the compounding ratio of the polyhydric alcohol compound (B) is less than 1% by weight, the effect of improving mechanical properties such as flexibility and impact resistance is not observed, and when it is more than 50% by weight, extrusion moldability is deteriorated. It is not preferable because deterioration of blocker resistance and deterioration of future physical properties of PVA are observed.

As a blending method, a well-known method is usually used, that is, a method in which the components are melt-mixed in advance with an extruder, a roll kneader, a Banbury mixer, or the like, and each component is dry-blended and then extrusion-molded or injection-molded. Is used. The resin composition may be blended with other water-soluble polymers such as PVA having a low degree of polymerization, or conversely, other polymers, to the extent that the gist of the present invention is not impaired. Further, various additives such as colorants, antistatic agents, ultraviolet absorbers, heat stabilizers and lubricants can be added.

When a molded product is obtained from the resin composition of the present invention, it is melt-molded. Examples of the melt molding method include an injection molding method, an extrusion molding method, and a transfer molding method. The extrusion molding also includes blow molding, inflation molding, coextrusion molding, extrusion coating and the like.

As the injection conditions, for example, a cylinder temperature of 150 to 250 ° C., a mold temperature of about 10 to 100 ° C., and an injection pressure of about 500 to 2000 Kg / cm ² are adopted. The extrusion conditions include, for example, a die temperature of 150.
It is preferable that the temperature is set to about 250 ° C and the temperature of the screw compression portion is set to a temperature about 5 to 30 ° C higher than the temperature of the discharge portion.

Further, as a substrate used when a laminated film is obtained using the resin composition of the present invention, a saponified product of ethylene-vinyl acetate copolymer, polyethylene, ethylene-
Ethyl acrylate copolymer, ionomer, ethylene-
Propylene copolymer, poly-4-methyl-pentene-1
Such as olefin resin, polyvinylidene chloride, vinylidene chloride-vinyl chloride copolymer, vinylidene chloride-acrylonitrile copolymer, etc. vinylidene chloride resin, polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, polyester, nylon 6, nylon 11, polyamides such as nylon 66, and unsaturated carboxylic acid-modified polyolefins obtained by grafting an unsaturated carboxylic acid such as maleic anhydride onto a polyolefin. As a method for obtaining a laminated film, known methods such as extrusion laminating method and dry laminating method are used.

There are no particular restrictions on the form of the molded article obtained using the resin composition of the present invention, and bottles (particularly agricultural chemical bottles), films, sheets, hoses, tubes, containers,
Examples include bags, fibers, foams, stationery, office supplies, hygiene products, medical supplies, agricultural and horticultural products, machine parts and the like. In addition to molded products, hot melt adhesives, paper processing agents, fiber processing,
It is used in various applications such as molding processing aids and packaging materials.

[0025]

The polyhydric alcohol compound (B) containing 3 or more hydroxyl groups and 3 or more carbon atoms and having a melting point of 50 ° C or higher and lower than 300 ° C is added to the PVA-based resin (A) containing an oxyalkylene group. By blending 1 to 50% by weight, the water-solubility is not impaired, the mechanical properties such as impact strength and flexibility of the molded product made of such a resin composition and its stability over time are good, and A PVA-based resin composition having improved adhesiveness with the base material can be obtained.

[0026]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples. In the examples, "%" means weight basis unless otherwise specified. Example 1 Oxyalkylene group-containing PVA (A) Average degree of polymerization: 480 Polyoxyethylene monoallyl ether (where X is a methyl group in Chemical formula 1) (average degree of condensation of oxyethylene is 10) Copolymerization ratio of units: 2.0 Mol% Ratio of oxyalkylene units in the whole polymer: 1
6.0 wt% Saponification degree of vinyl acetate component: 95 mol% MFI: 3.5 g / 10 min. The MFI value is a melt indexer (nozzle 2.095 mmφ × 8 mm) manufactured by Toyo Seiki Seisakusho KK The load was 2160 g, and the measurement was performed at 210 ° C. The MFI was similarly measured in the following examples and comparative examples.

Polyhydric alcohol compound (B) pentaerythritol Melting point: 180 ° C.

The above resin was supplied to a twin-screw extruder (in the same direction, 35 mmφ) in the compounding ratio shown in Table 1 and extruded at a temperature of 220 ° C. to obtain a pellet-shaped resin composition. The molding pellets are supplied to an injection molding machine, the cylinder maximum temperature is 220 ° C., the mold temperature is 60 ° C., the injection pressure is 800 Kg / c.
The following test pieces were prepared by injection molding under the condition of m ² , and the mechanical properties were measured under the following conditions. Also, for the evaluation of adhesiveness, a three-layer three-layer film (oxyalkylene group-containing PVA / adhesive resin / low-density polyethylene = 20/10 / 25μ) by coextrusion method (die temperature 210 ° C.) using the pellet and low-density polyethylene Was prepared and the adhesiveness was evaluated under the following conditions. Admer NF as an adhesive resin
-550 (manufactured by Mitsui Petrochemical Industry Co., Ltd.) was used.
The measurement results are shown in Table 1. The same evaluations as in Example 1 were performed on Examples 2 to 7 and Comparative Examples 1 to 5 shown below.

(Test Pieces) Pellets were molded into JIS K 7113 No. 6 dumbbells and JIS K 7110 No. 2 test pieces with an injection molding machine. (Tensile elastic modulus) Measured according to JIS K 7113 Test piece: No. 6 dumbbell Tensile speed: 5 mm / min Measuring atmosphere: 20 ° C, 65% RH (Izod impact strength) Measured according to JIS K7110 Test piece: 2 No. Test piece (square column) Measuring atmosphere: 20 ° C, 65% RH Hammer lifting angle 150 ° Impact speed: 3.5 m / sec (Adhesiveness) Using a tensile tester, peeling speed 300 mm / The adhesive strength was measured at min.

Example 2 PVA with oxyalkylene group (A) Average degree of polymerization: 480 Polyoxyethylene vinyl ether (X in formula 2 is hydrogen)
(The average degree of condensation of oxyethylene is 30) Copolymerization ratio of units: 1.5 mol% Ratio of oxyalkylene units in the entire polymer: 2
6.2 wt% Saponification degree of vinyl acetate component: 99 mol% MFI: 3.8 g / 10 minutes

Polyhydric alcohol compound (B) Sorbitol Melting point: 110 ° C.

Example 3 Oxyalkylene group-containing PVA (A) Average degree of polymerization: 460 Polyoxyethylene monoallyl ether (where X is a methyl group in Chemical Formula 1) (average degree of condensation of oxyethylene is 10) Copolymerization ratio of units: 3.5 mol% Ratio of oxyalkylene units in the whole polymer: 2
4.4% by weight Saponification degree of vinyl acetate component: 94 mol% MFI: 6.0 g / 10 minutes

Polyhydric alcohol compound (B) pentaerythritol Melting point: 180 ° C.

Example 4 PVA (A) containing oxyalkylene group Average degree of polymerization: 580 Polyoxyethylene vinyl ether (X in formula 2 is hydrogen)
(The average degree of condensation of oxyethylene is 10) Copolymerization ratio of units: 1.0 mol% Ratio of oxyalkylene units in the entire polymer:
8.8 wt% Saponification degree of vinyl acetate component: 96 mol% MFI: 1.0 g / 10 min

Polyhydric alcohol compound (B) Mannitol melting point: 166 ° C.

Example 5 PVA (A) containing oxyalkylene group Average degree of polymerization: 730 Polyoxyethylene monoallyl ether (where X is n in Chemical Formula 1)
-Butyl group) (average degree of condensation of oxyethylene is 10) Copolymerization ratio of units: 2.6 mol% Ratio of oxyalkylene units in the entire polymer: 1
9.8 wt% Saponification degree of vinyl acetate component: 95 mol% MFI: 0.2 g / 10 min

Polyhydric alcohol compound (B) Polyglycerin Melting point: Liquid at room temperature

Example 6 PVA (A) containing oxyalkylene group Average degree of polymerization: 430 Polyoxyethylene vinyl ether (where X is n-butyl group in Chemical formula 2) (average degree of condensation of oxyethylene is 5) Copolymerization ratio of units: 5.0 mol% Ratio of oxyalkylene units in the whole polymer: 1
9.4 wt% Saponification degree of vinyl acetate component: 99 mol% MFI: 10 g / 10 minutes

Polyhydric alcohol compound (B) pentaerythritol Melting point: 180 ° C.

Example 7 PVA (A) Containing Oxyalkylene Group Average Degree of Polymerization: 375 Polyoxyethylene monoallyl ether (X in formula 1 is an ethyl group) (oxyethylene has an average degree of condensation of 20) Copolymerization ratio of units: 1.5 mol% Ratio of oxyalkylene units in the whole polymer: 2
2.7% by weight Saponification degree of vinyl acetate component: 99 mol% MFI: 25 g / 10 minutes

[0041]Polyhydric alcohol compound (B) Pentaerythritol Melting point: 180 ° C

Example 8 Oxyalkylene group-containing PVA (A) Average degree of polymerization: 480 Polyoxyethylene vinyl ether (X in formula 2 is hydrogen)
(The average degree of condensation of oxyethylene is 15) Copolymerization ratio of units: 0.07 mol% Ratio of oxyalkylene units in the whole polymer:
1.03 wt% Saponification degree of vinyl acetate component: 99 mol% MFI: 3.4 g / 10 minutes

Polyhydric alcohol compound (B) pentaerythritol Melting point: 180 ° C.

Comparative Example 1 Oxyalkylene group-containing PVA (A) Average degree of polymerization: 480 Polyoxyethylene monoallyl ether (X in formula 1 is hydrogen) (Average degree of condensation of ethylene oxide is 10) Copolymerization ratio of units: 2. 0 mol% Ratio of oxyalkylene units in the whole polymer: 1
6.0 wt% Saponification degree of vinyl acetate component: 95 mol% MFI: 3.5 g / 10 min

Comparative Example 2 Oxyalkylene group-containing PVA (A) Average degree of polymerization: 480 Polyoxyethylene monoallyl ether (X in formula 1 is hydrogen) (average degree of condensation of ethylene oxide is 10) Copolymerization ratio of units: 2. 0 mol% Ratio of oxyalkylene units in the whole polymer: 1
6.0 wt% Saponification degree of vinyl acetate component: 95 mol% MFI: 3.5 g / 10 min

Polyhydric alcohol compound (B) Glycerin Melting point: 19 ° C.

Comparative Example 3 PVA (A) containing oxyalkylene group Average degree of polymerization: 480 Polyoxyethylene vinyl ether (X in formula 2 is hydrogen)
(The average degree of condensation of ethylene oxide is 10) Copolymerization ratio of units: 2.0 mol% Ratio of oxyalkylene units in the whole polymer: 1
6.0 wt% Saponification degree of vinyl acetate component: 95 mol% MFI: 3.5 g / 10 min

Polyhydric alcohol compound (B) pentaerythritol Melting point: 180 ° C.

Comparative Example 4 PVA (A) containing oxyalkylene group Average degree of polymerization: 480 Polyoxyethylene monoallyl ether (X in formula 1 is hydrogen) Copolymerization ratio of units (average degree of condensation of ethylene oxide is 10): 2. 0 mol% Ratio of oxyalkylene units in the whole polymer: 1
6.0 wt% Saponification degree of vinyl acetate component: 95 mol% MFI: 3.5 g / 10 min

Polyhydric alcohol compound (B) trimethylene glycol Melting point: liquid

Comparative Example 5 PVA (A) containing oxyalkylene group Average degree of polymerization: 480 Polyoxyethylene vinyl ether (X in formula 2 is hydrogen)
(The average degree of condensation of ethylene oxide is 10) Copolymerization ratio of units: 2.0 mol% Ratio of oxyalkylene units in the whole polymer: 1
6.0 wt% Saponification degree of vinyl acetate component: 95 mol% MFI: 3.5 g / 10 min

Polyhydric alcohol compound (B) ethylene glycol melting point: -12 ° C

Comparative Example 6 Evaluation was carried out in the same manner as in Example 3 except that the blending amount of the polyhydric alcohol (B) was 60% by weight.

[0054]

[Table 1] EO-PVA / Tensile elastic modulus Izod impact strength Adhesive Polyhydric alcohol (Kg / cm ² ) (Kg-mm / mm) (g / 15mm) compounding weight ratio A B A B A B Example 1 90/10 1850 1860 16.0 15.8 380 370 Example 2 95/5 2000 2010 17.5 17.1 380 380 Example 3 85/15 1700 1700 18.6 18.3 370 380 Example 4 80/20 1500 1450 15.0 15.2 370 370 Example 5 55 / 45 1200 1220 22.0 21.6 330 340 Example 6 70/30 1300 1290 20.0 19.9 360 350 Example 7 98/2 2100 2080 12.9 13.0 380 380 Example 8 80/20 2800 2700 9.2 9.1 320 310 Comparative Example 1 100/0 3000 3000 1.8 1.8 380 380 Comparative Example 2 90/10 1700 2670 16.0 7.6 260 180 Comparative Example 3 99.5 / 0.5 2920 2980 1.9 1.9 380 380 Comparative Example 4 90/10 2100 2760 8.9 2.8 280 160 Comparative Example 5 90/10 2230 2790 12.6 3.9 280 140 Comparative example 6 40/60 1060 2310 6.7 3.9 240 240 (Note) EO-PVA: oxyalkylene group-containing PVA a: test piece or three-kind three-layer film just created measurement results B: test piece or three After creating the layer film 20 ° C., 65%
Measurement results after left for 1 month under RH conditions

[0055]

EFFECT OF THE INVENTION A polyhydric alcohol compound (B) containing 3 or more hydroxyl groups and 3 or more carbon atoms in the PVA-based resin (A) containing an oxyalkylene group and having a melting point of 50 ° C. or higher and less than 300 ° C. 1 to 50% by weight of the resin composition does not impair the water solubility and has good mechanical properties such as impact strength and flexibility of a molded product made of such a resin composition and its stability over time, Furthermore, a PVA-based resin composition having improved adhesion to other base materials is obtained, which is very useful.

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Claims (3)

(57) [Claims] 1. A polyhydric alcohol compound containing 3 or more hydroxyl groups and 3 or more carbon atoms in a polyvinyl alcohol resin (A) containing an oxyalkylene group and having a melting point of 50 ° C. or higher and lower than 300 ° C. A polyvinyl alcohol-based resin composition comprising 1) to 50% by weight of B). 2. The polyvinyl alcohol-based resin (A) containing an oxyalkylene group has a saponification degree of 80 to 100 mol%, and an average degree of condensation of oxyalkylene groups is 3 to 100,
The polyvinyl alcohol resin composition according to claim 1, wherein the content ratio of the oxyalkylene group is 0.1 to 30 mol%. 3. The polyvinyl alcohol resin composition according to claim 1, wherein the polyhydric alcohol compound (B) is at least one selected from pentaerythritol, mannitol, sorbitol, polyglycerin, fructose and glucose. .