JPH06263954A - Composition and laminate - Google Patents

Abstract

PURPOSE:To obtain a composition excellent in biodegradability, moldability, mechanical strength, etc., useful for packaging films, sheets, agricultural applications, etc., comprising a vinyl alcohol-type polymer and a specific high- molecular weight aliphatic polyester. CONSTITUTION:The objective composition comprises (A) 2-98wt.% of a vinyl alcohol-based polymer (e.g. polyvinyl alcohol, vinyl alcohol-based copolymer) and (B) 98-2wt.% of a high-polymerization degree aliphatic polyester 5000-500000 in number-average molecular weight prepared by incorporating an aliphatic polyester having >=3000 number-average molecular weight with >=4C dicarboxylic acid as a constituent (pref. succinic acid) with a diisocyanate (e.g. hexamethylene diisocyanate). As the case may be, it is preferable that this composition be incorporated with 0.001-1wt.% of a plasticizer, thermal stabilizer, etc.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a resin composition which is not easily decomposed in the natural world, in order to solve the problems of environmental destruction and waste disposal, not only in the natural environment such as landfill but also in sewage treatment plants. The present invention relates to a composition exhibiting good biodegradability even in the treatment under aerobic conditions carried out in (1) and excellent in melt moldability, mechanical strength, water resistance and gas barrier property, and a laminate using the same.

[0002]

2. Description of the Related Art Conventionally, polyethylene, polypropylene, polyamide, polyethylene terephthalate, etc. have been used as films, containers, agricultural / civil engineering sheets, films and various molded products for packaging various products such as foods, all of which are environmental It is not decomposed inside and remains in the soil as it is in landfills, which is an environmental problem. So it collapses in the environment,
There is an urgent need to develop degradable plastics. As a material that disintegrates in the environment, there is a method of blending a biodegradable starch or the like with a non-biodegradable resin, but the shape is lost and it cannot be said to be essential. Also, as biodegradable plastics, aliphatic polyesters, aliphatic polyesteramides, polypeptides, cellulose, starch, chitosan, etc. are known, but have low melting points or lack mechanical strength. However, they are often poor in water resistance and costly.

[0003]

The present invention was devised to solve the drawbacks of the prior art, and has essential biodegradability, moldability, mechanical strength and water resistance, and gas barrier property. However, it is an object of the present invention to provide a composition whose degree can be controlled depending on the blend composition.

[0004]

[Means for Solving the Problems] The above-mentioned objects are as follows. A dicarboxylic acid having a vinyl alcohol polymer (A) of 2 to 98% by weight and a number average molecular weight of 3,000 to 500,000 and having a carbon number of 4 or more as a dicarboxylic acid component. This is achieved by providing a composition consisting of 98-2% by weight of the aliphatic polyester used.

In the present invention, in order to obtain a composition having excellent gas barrier properties of a vinyl alcohol polymer and biodegradability without impairing the mechanical strength, the vinyl alcohol polymer is contained in an amount of 50 to 98% by weight. A composition comprising 50 to 2% by weight of an aliphatic polyester polymer is suitable.

Further, in the present invention, in order to obtain a composition having excellent mechanical strength without impairing the biodegradability and water resistance of the aliphatic polyester polymer, the vinyl alcohol polymer content is set to 2 to 50% by weight. A composition comprising 98 to 50% by weight of an aliphatic polyester polymer is suitable. In the present invention, by blending the aliphatic polyester and the vinyl alcohol-based polymer, the excellent gas barrier properties and mechanical strength of the vinyl alcohol-based polymer are expressed without impairing the biodegradability of the aliphatic polyester. Is amazing. 2% vinyl alcohol polymer
If it is less than the above range, gas barrier properties and mechanical strength are insufficient. When the aliphatic polyester content is less than 2%, the biodegradation rate is slow.

Examples of the dicarboxylic acid component having 4 or more carbon atoms in the aliphatic polyester in the present invention include succinic acid, terephthalic acid, isophthalic acid, adipic acid, azelaic acid, sebacic acid and dodecanoic acid, and the diol component is ethylene. Glycol, propylene glycol, 1.
3-butanediol, 1.4-butanediol, 1,5
-Pentanediol, 1.6-hexanediol, 1,
8-octanediol, 1,9-nonanediol, diethylene glycol and the like can be mentioned. Of these, succinic acid is preferable as the dicarboxylic acid, and ethylene glycol, propylene glycol, and 1,4-butanediol are preferable as the diol component. In the present invention, it is essential to use a dicarboxylic acid component having a carbon number of 4 or more as the dicarboxylic acid component, but a dicarboxylic acid having a carbon number of 3 or less can be used in combination within the range where the object of the present invention is not impaired. By combining such succinic acid with a diol, it is possible to obtain the effects of less gel generation, higher polymerization degree, and excellent mechanical strength, elongation, transparency and biodegradability.

Since it is difficult to increase the degree of polymerization of the aliphatic polyester according to the present invention by a usual polymerization method, a polyester having a number average molecular weight of 3000 or more is once obtained by a usual polymerization method such as a bulk polymerization method. Then, it is preferable to increase the degree of polymerization by the method described below in order to improve productivity.

The number average molecular weight after increasing the degree of polymerization is 5,000 or more and 500,000 or less, preferably 20,000 or more and 2,000.
It is 00 or less. If the number average molecular weight is less than 5,000, the melt moldability is poor, and the strength is insufficient, which is unsuitable.
If it exceeds 000, the melt moldability and processability are poor. Other methods for increasing the degree of polymerization include methods using oxazoline, carbodiimide, phenyl oxalate, and phenyl carbonate in addition to solid-state polymerization, but the method for increasing the degree of polymerization with diisocyanate is easy. It is preferable that a high degree of polymerization can be achieved and that the biodegradation rate is high.

As the diisocyanate, hexamethylene diisocyanate, xylene diisocyanate, 1,
6-naphthylene diisocyanate, 2,4-tolylene diisocyanate and the like can be mentioned.

In the present invention, the vinyl alcohol-based polymer is not particularly limited as long as it is a polymer having a vinyl alcohol unit, but typical examples thereof include polyvinyl alcohol and vinyl alcohol-based copolymers. The saponification degree of the vinyl alcohol polymer is preferably 50 mol% or more, and when it is less than 50 mol%, the gas barrier property and biodegradability are insufficient. The vinyl alcohol-based copolymer is typically an ethylene-vinyl alcohol copolymer having an ethylene content of 65 mol% or less, preferably 60 mol% or less, and more preferably 55 mol% or less. When the ethylene content is higher than 65 mol%, the gas barrier property is insufficient and the biodegradability is poor.

The method for obtaining the composition of the vinyl alcohol polymer and the aliphatic polyester polymer is not particularly limited, but a method of dry blending pellets or powder of both, a Banbury mixer or both There is a method of obtaining pellets by melt-kneading with a single-screw or twin-screw extruder. If the blending is insufficient, or if foreign substances are mixed during blending, or if heat-degraded products are generated, it may be broken during melt molding, cracks, or unevenness may occur. It is desirable to seal the hopper mouth with nitrogen at the lowest possible temperature.

In the present invention, other components may be added to the extent that their purpose is not hindered. Specifically, polyethylene, polypropylene, ethylene-propylene copolymer, polybutylene and lubricants, plasticizers, compatibilizers, colorants, heat stabilizers, deodorants, ultraviolet absorbers, antibacterial agents, fungicides, oxidation Inhibitors, talc, clay, mica, silica, titanium oxide, calcium carbonate, metals, fine powders of metal oxides can be mentioned.

Further, when blending, a plasticizer, a heat stabilizer, an ultraviolet absorber, and
There is no problem in adding additives such as antioxidants, antibacterial agents, antifungal agents and fillers. In particular, in order to prevent gel generation due to blending, one or a combination of hydrotalcite-based, hindered phenol-based, hindered amine-based heat stabilizers and higher aliphatic carboxylic acid salts is used in an amount of 0.001 to 0.001. It is preferable to add 1% by weight.

Next, the composition of the present invention is a monolayer film,
It is molded into a single-layer molded product such as a sheet or yarn, or a multilayer laminated product. The method for obtaining a single-layer molded product is not particularly limited, and a melt extrusion method, a wet method, a dry molding method or the like is used.
The multilayer laminate can be obtained by laminating a biodegradable layer on both sides or one side of a layer made of the composition of the present invention. As the biodegradable layer here, an aliphatic polyester, an aliphatic polyesteramide,
Examples include not only starch, cellulose, polysaccharides such as carrageenan, chitosan, pullulan, etc., but also various metals and various inorganic substances. The adhesive used for obtaining a laminate of the composition according to the present invention and the above-mentioned biodegradable layer is not particularly limited, but a polyurethane resin, a starch resin,
Those having biodegradability, such as those obtained by grafting an unsaturated carboxylic acid or its anhydride onto a polyolefin-based polymer or copolymer, are preferable. Examples of the method for obtaining the laminate include methods such as extrusion, coextrusion, dry lamination, thermocompression bonding, and solution coating via an adhesive in the middle.

Next, the single layer or the laminate can be stretched by heating at a temperature not higher than the melting point of the vinyl alcohol polymer by vacuum pressure forming or the like, and the laminate can be biaxially stretched with a film. It is also possible to put it in the above and heat-stretch. The composition according to the present invention can also be a biaxially stretched blow component by co-injection by biaxially stretched blow molding or in combination with other resins.

The structure of the laminate is not particularly limited,
Examples are vinyl alcohol polymer composition layer / biodegradable layer, biodegradable layer / vinyl alcohol polymer composition layer / biodegradable layer. Needless to say, when biodegradable layers are used on both sides, the two materials may be different. The composition according to the present invention and the film, sheet and molded product using the same are not only used in fields requiring gas barrier properties by utilizing their biodegradability, but also in mulch film, house film, pots for raising seedlings, agricultural chemicals. Agricultural fields such as bottles and bags for fertilizer,
Packaging for keeping freshness of fresh flowers, the field of civil engineering, diapers,
Sanitary items, wet tissues, medical applications,
It can be applied to the fields of fisheries such as fishnets and Tegus, and the fields of textiles. According to the present invention, a composition having excellent barrier properties, strength, elongation, transparency and biodegradability can be obtained, and the balance can be controlled by appropriately selecting the composition ratio. .

[0018]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples. The number average molecular weight as referred to in the present invention is measured by GP.
According to method C. However, polystyrene is the standard,
Measuring device: WATER HLC-510, column: Z
ORBAX PSM1000S and PSM60S, solvent:
(Hexachloroisopropanol / chloroform = 2 /
5% acetic acid mixed with the mixed solvent of 8), solution concentration:
0.1% by weight, injection amount: 5 μl, flow rate: 1.0 ml /
Minute, temperature: measured under the conditions of column 40 ° C. and detector UV (254 nm).

Example 1 As a vinyl alcohol polymer, ethylene content 32 mol%, saponification degree 99.7 mol%, 190 ° C., load 216.
Melt flow rate at 0 g is 1.3 g / 10 mi
30 parts of an ethylene-vinyl alcohol copolymer of n was esterified with succinic acid and ethylene glycol to polymerize to obtain an aliphatic polyester having a number average molecular weight of 15,000, and then the polymerization degree was increased with hexamethylene diisocyanate. The number average molecular weight was 34,000. 70 parts of the aliphatic polyester polymer was melt-kneaded at 200 ° C. in a nitrogen atmosphere in a vent type twin screw type 20φ extruder to prepare pellets. The pellets were melt extruded at 200 ° C. with a 20φ extruder to form a film having a thickness of 20 μm and 50 ° C. The film was conditioned at 20 ° C. and 65% RH.

Example 2 As a vinyl alcohol polymer, the ethylene content was 44 mol%, the saponification degree was 99.7 mol%, 190 ° C., and the load was 216.
Melt flow rate at 0 g is 5.8 g / 10 mi
A film was obtained in the same manner as in Example 1 except that n was used.

Example 3 A film was obtained in the same manner as in Example 1 except that 70% by weight of the vinyl alcohol polymer and 30% by weight of the aliphatic polyester polymer described in Example 1 were added.

Example 4 A film was obtained in the same manner as in Example 2 except that 70% by weight of the vinyl alcohol polymer and 30% by weight of the aliphatic polyester polymer described in Example 2 were added.

Example 5 The vinyl alcohol polymer described in Example 1 had an ethylene content of 32 mol%, a saponification degree of 85 mol%, and 190 ° C.
Melt flow rate at a load of 2160g is 3.5g
A film was obtained in the same manner as in Example 1 except that / 10 min was used.

Example 6 The vinyl alcohol polymer described in Example 3 had an ethylene content of 32 mol%, a saponification degree of 90 mol%, and 190 ° C.
Melt flow rate at a load of 2160g is 2.7g
A film was obtained in the same manner as in Example 3 except that the film having a length of / 10 min was used.

Example 7 Using succinic acid and 1.4-butanediol, an aliphatic polyester having a number average molecular weight of 12000 was obtained.
The polymerization degree was increased with 4-tolylene diisocyanate. The number average molecular weight was 39,000. Otherwise, Example 3
A film was obtained in the same manner as in.

Example 8 A film was obtained in the same manner as in Example 3 except that PVA having 0 mol% of ethylene and 70 mol% of saponification was used as the vinyl alcohol polymer described in Example 3.

Example 9 A film was obtained in the same manner as in Example 1 except that PVA having 0 mol% of ethylene and 70 mol% of saponification was used as the vinyl alcohol polymer described in Example 1.

Example 10 A laminate was prepared by dry lamination using the pellets prepared in Example 3 as an intermediate layer and polycaprolactone as an outer layer with a urethane adhesive. Thickness composition is 3
It was 00μ / 30μ / 300μ. This was thermoformed into a cup shape at 150 ° C. by a vacuum pressure air forming machine.

Example 11 A laminate was prepared by dry lamination using the pellets prepared in Example 3 as an intermediate layer and a composition of 40% by weight of starch and 60% by weight of low density polyethylene as an outer layer. The thickness configuration is 300 μ / 50 μ / 300 μ. This was thermoformed into a cup shape at 150 ° C. by a vacuum pressure air forming machine.

Comparative Example 1 A film was obtained in the same manner as in Example 1 except that 99% by weight of the vinyl alcohol polymer described in Example 1 and 1% by weight of the aliphatic polyester polymer were added.

Comparative Example 2 A film was prepared in the same manner as in Example 1 except that the composition containing 1% by weight of the vinyl alcohol polymer described in Example 1 and 99% by weight of the aliphatic polyester polymer was used. Obtained.

[0032]

[Table 1]

Elongation at break: A melt-extruded film having a thickness of 20 μ (a laminated body is a body portion of a molding cup) is 20 by a tensile tester.
Elongation when ruptured by pulling under conditions of ° C and 65% RH. A: 250% or more, B: 100 to 250%, C: 100
Less than% Transparency: A melt extruded film having a thickness of 50 μ (a laminated body is a body portion of a molding cup) is visually evaluated. A: Transparent, B: Slightly cloudy, C: Opaque Biodegradability: The body of the film or laminate was punched out in a dumbbell shape (JIS K7127 type 2) and embedded in the soil, and taken out after 3 months. AA ... The shape is not retained. A: Holds part of the shape. B ... ・ The shape is retained, but it is partially disassembled. C ... Invariant barrier property: oxygen permeability of the body of the melt-extruded film or laminate at 20 ° C. and 85% RH (MOCON method,
Unit: cc. 20 μ / m ² . day. atm)

[0034]

According to the present invention, a composition and a laminate having biodegradability, moldability, mechanical strength, water resistance and gas barrier property can be obtained.

Claims (4)

[Claims] 1. A vinyl alcohol polymer (A) 2 to 9
8% by weight and number average molecular weight of 3,000 or more and 50,000 or more
A composition comprising 98 to 2% by weight of an aliphatic polyester (B) which is 0 or less and uses a dicarboxylic acid component having 4 or more carbon atoms as a dicarboxylic acid component. 2. A vinyl alcohol polymer (A) 2 to 9
8% by weight and a number average molecular weight of 3,000 or more, and a high polymerization of 5,000 or more and 500,000 or less obtained by increasing the degree of polymerization of an aliphatic polyester using a dicarboxylic acid having a carbon number of 4 or more as a dicarboxylic acid component. A composition comprising 98 to 2% by weight of an aliphatic polyester (B). 3. A vinyl alcohol polymer (A) 2 to 9
8 wt% and a number average molecular weight of 3,000 or more, and a number average molecular weight of 5,000 or more and 50,000 obtained by adding diisocyanate to an aliphatic polyester using a dicarboxylic acid having a carbon number of 4 or more as a dicarboxylic acid component.
A composition comprising 98 to 2% by weight of a high degree of polymerization aliphatic polyester (B) of 0 or less. 4. A laminate having a layer having biodegradability on one side or both sides of the layer of the composition according to any one of claims 1 to 3.