JPH11116761A - Polyvinyl alcohol type resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition which provides a molded article with excellent mechanical strength, impact resistance, morphological stability and dimensional stability by compounding a PVA type resin with a specific amount of an organic waste material. SOLUTION: There is provided a composition composed of 100 pts.wt. of a PVA type resin and 3-500 pts.wt. of an organic waste material, preferably bean-curd refuse, coffee bean refuse, malt refuse, soy refuse, strained draff of an apple, skin of an orange, sludge or kitchen refuse. As the PVA type resin, is preferably employed a PVA having a degree of polymerization of 200-5,000, preferably of 300-2,000 and a degree of saponification of 90-100 mol.%, preferably 95-100 mol.%, or a hydrophobic group-modified PVA containing 0.1-20 mol.%, preferably 3-15 mol.% of preferably up to 20C α-olefin units and having a degree of polymerization of 200-5,000 and a degree of saponification of 90-100 mol.%, preferably 95-100 mol.%. This composition is also excellent in natural degradability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a polyvinyl alcohol resin composition. More specifically, the present invention relates to a polyvinyl alcohol-based resin composition capable of obtaining a molded product that collapses naturally after being buried in soil.

[0002]

2. Description of the Related Art In recent years, effective use of earth resources has been called for. Plastics are also being addressed in the direction of reuse and heat recovery. In addition, there is a limit on incineration and burial, especially in urban areas, with regard to waste disposal. Okara and coffee bean lees, malt lees, soy sauce lees, apple lees, orange peel, sludge, and other food wastes such as garbage also have similar problems, and their effective use is required. Already, there have been proposals for mixing okara with general-purpose plastics to make packaging materials. However, such a combination has not been widely used because it has poor natural disintegration properties and cannot obtain general-purpose physical properties.

On the other hand, polyvinyl alcohol (hereinafter referred to as PVA)
It is known that resin is generally superior in strength and toughness and mechanical strength is superior to other plastics. It is used for coating film, fiber paste, and paper. Widely used in medicines and the like. Also PVA
Is a typical water-soluble resin, which has a property of dissolving and losing its shape when in contact with water, although the dissolution rate varies depending on the degree of saponification of PVA. However, PVA
The molded article is hard and has a high elastic modulus immediately after molding, but has a problem in that when it is left under high humidity for a long time, it absorbs moisture and its shape, strength, elongation, elastic modulus and the like are greatly changed. In order to solve this problem, for example, the addition of various additives,
Attempts have been made to increase the degree of saponification of VA as much as possible to increase the crystallinity of the resin. However, none of them presents new problems and has not been sufficiently solved at present.

[0004] Conventionally, it is common practice to mix inorganic fillers such as talc, clay and calcium carbonate. In this case, the initial strength and elastic modulus are increased, and the hardness and weight are given. When left untreated, the physical properties often change over time, and in most cases, the form stability is not improved at all. In addition, there is a problem that the impact resistance also decreases with the blending amount of the inorganic filler, and the solution has not been solved. The molded product obtained by increasing the degree of saponification of PVA and increasing the crystallinity of the resin has a low moisture absorption rate,
Even when moisture is absorbed, the initial strength and elastic modulus are easily maintained, and the form stability is relatively good, but there is a problem that the melt moldability is greatly limited. That is, when the degree of saponification is increased, the melting point of PVA increases, and the decomposition temperature of PVA and the molding temperature become extremely close, so that stable molding conditions cannot often be obtained. For this reason, usually, a large amount of a plasticizer or the like is added to lower the melting point, and molding is performed. However, due to the addition of the plasticizer, there is a problem that the hygroscopicity is increased and the form stability is greatly reduced. Moreover, such high saponification degree P
Even with a VA molded product, high impact strength was not obtained.

[0005]

SUMMARY OF THE INVENTION Under such circumstances, the present invention provides a molded article having excellent mechanical strength and impact resistance, good form stability and dimensional stability, and high hardness and rigidity. It is an object of the present invention to provide a PVA-based resin composition capable of being used.

[0006]

Means for Solving the Problems In order to develop a PVA-based resin composition having the above-mentioned preferable properties, the present inventors have made an effort to develop a PVA-based resin composition.
As a result of intensive studies, a PVA comprising 100 parts by weight of the PVA-based resin (A) and 3 to 500 parts by weight of the organic waste material (B) was used.
A resin composition was found. Further, the present invention provides a molded product obtained by melt-molding the resin composition.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the resin composition of the present invention,
A PVA-based resin is used as the component (A). Various PVA-based resins can be used as such a PVA resin, but in order to obtain a molded article having excellent water resistance, unmodified PVA having high crystallinity or hydrophobic group-modified PVA is preferable. As the unmodified PVA, those having a degree of polymerization of 200 to 5000 and a degree of saponification of 90 to 100 mol% are preferable. If the degree of polymerization is less than 200, the strength of the molded product is insufficient, and if it is more than 5000, the viscosity is increased and the moldability is deteriorated. In consideration of the strength properties and moldability of the molded product, a more preferable range is 300 to 2,000. A preferred range of the degree of saponification is 95 mol% or more. If the saponification degree is less than 90 mol%, the water resistance of the molded product is insufficient.

As the hydrophobic group-modified PVA, for example, 0.1 to 20 mol% of an α-olefin unit having 20 or less carbon atoms is used.
PVA-based resin containing 0.1-20 mol% of a vinyl ether unit containing a long-chain alkyl group having 20 or less carbon atoms
PVA-based resin containing 0.1 to 20 mol% of a hydroxyl group-containing α-olefin unit having 20 or less carbon atoms
A PVA-based resin to be contained and a PVA-based resin having a terminal of a long-chain alkyl group having 4 to 50 carbon atoms at the end thereof are mentioned.
A PVA-based resin containing 20 mol% is preferred. Preferably, these hydrophobic group-modified PVAs have a degree of polymerization of 200 to 5,000 and a degree of saponification of 90 to 100 mol%. become worse. A preferred range of the degree of saponification is 95 mol% or more. If the saponification degree is less than 90 mol%, the water resistance of the molded product is insufficient. As the α-olefin having 20 or less carbon atoms, ethylene, propylene,
Isobutylene is more preferred in terms of productivity. The content of the α-olefin unit is from 0.1 to 20 mol%, more preferably from 3 to 15 mol%.
When the α-olefin unit is less than 0.1 mol%, the effect of modification is not exhibited, and when it exceeds 20 mol%, the disintegration of the molded product in the soil decreases.

The PVA resin used in the present invention is obtained by saponifying a vinyl ester polymer by a conventional method. Examples of the vinyl ester include vinyl formate, vinyl acetate, vinyl propionate, vinyl pivalate, and vinyl versatate, with vinyl acetate being preferred. As the PVA-based resin of the present invention, a resin obtained by copolymerizing another copolymerizable unsaturated monomer can be used as long as the effects of the present invention are not impaired. Examples of such unsaturated monomers include, for example, unsaturated acids such as acrylic acid, methacrylic acid, (anhydride) maleic acid, (anhydride) itaconic acid, acrylamide and its derivatives, N-vinylpyrrolidone, N-vinylacetamide , N-vinylformamide, vinylsilanes, and unsaturated compounds containing a polyoxyalkylene group.

On the other hand, in the composition of the present invention, organic waste materials used as the component (B) include okara, coffee beans cake, malt cake, soy sauce cake, apple cake, mandarin peel, sludge, raw One or more types selected from garbage. Such organic waste materials are effective as fillers not only for cost reduction, but also for increasing the hardness and rigidity of molded products, and for adjusting the speed of natural disintegration when buried in soil. is there. The amount of the organic waste is 100 parts by weight of the PVA-based resin.
3-500 parts by weight are preferred. 3 organic waste materials
If the amount is less than parts by weight, the effect of the compounding is not recognized. If it exceeds 500 parts by weight, not only does the moldability decrease, but also the strength and toughness of the molded product decrease. As these organic waste materials, orange peel and garbage are relatively finely shredded, but those containing water or dried powder can also be used.

The PVA-based resin composition of the present invention may optionally contain a water-disintegrable or biodegradable resin as long as the object of the present invention is not impaired. Examples of such a water-disintegrable or biodegradable resin include polycaprolactone, polylactic acid, polyethylene succinate, chemically synthesized resins such as polybutylene succinate, starch, chitin, and resins using natural products such as chitosan. And microbial resins such as hydroxybutyric acid / hydroxyvaleric acid copolymer, and these resins can be used alone or in a blend of two or more. In addition, polyolefin, polystyrene,
General-purpose thermoplastic resins such as nylon and vinyl chloride can also be blended as long as the object of the present invention is not impaired.

Further, if necessary, other additives such as fillers, plasticizers, coloring agents, fragrances, preservatives, lubricants, release agents, ultraviolet absorbers, heat stabilizers, flame retardants, rats, Additives such as repellents such as cockroaches can be appropriately compounded. Examples of fillers include fibrous substances such as cotton and glass fiber, talc, clay, calcium carbonate, silica, mica, alumina, titanium oxide, inorganic fillers such as zirconium oxide, boron nitride, and aluminum nitride, and urea-formalin resins. And organic fillers such as melamine-formalin-based resin. As a plasticizer, a material that has the effect of lowering the melting point, improving moldability, and imparting flexibility and toughness to a molded product, and that is generally used as a plasticizer for PVA, should be used. Can be. Examples of the plasticizer include glycerin, diglycerin,
With respect to polyhydric alcohols such as diethylene glycol, polyethers such as polyethylene glycol and polypropylene glycol, phenol derivatives such as bisphenol A and bisphenol S, and other amide compounds such as N-methylpyrrolidone, per mole of trihydric or higher polyhydric alcohol A compound to which about 2 to 4 moles of an alkylene oxide has been added, and water. The amount of the plasticizer is not particularly limited, but is preferably 0 to 100 parts by weight, more preferably 5 to 100 parts by weight, based on 100 parts by weight of the PVA-based resin.
It is in the range of ２０20 parts by weight.

The method for preparing the PVA-based resin composition of the present invention is not particularly limited. For example, a PVA-based resin, an organic waste material, and various additives used as desired are blended, and then melt-kneaded and pelletized. And a method in which a PVA-based resin blended with various additives used as desired and an organic waste material are separately kneaded in a kneading machine at a constant ratio, melt-kneaded, and then pelletized.
In the present invention, melt kneading is preferred.
After the VA-based resin is once made into an aqueous solution, an organic waste material can be added and used as a slurry. PV of the present invention
As a method for molding the A-based resin composition, when the above-mentioned slurry is used, the molding method is limited to press molding or the like, but when pellets are used, there is no particular limitation, and various known molding methods such as an injection molding method , Direct blow molding method,
An extrusion molding method such as a hollow molding method, a compression molding method, and a T-die extrusion molding method can be appropriately selected. The molded product thus obtained is excellent in form stability, dimensional stability and impact resistance, has hardness and rigidity, and can be used for various applications. For example, various containers, trays, sheets, films, and other molded products can be used.

[0014]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. In the examples, “%” is used unless otherwise specified.
And "part" represents a basis of weight.

Example 1 An ethylene content of 9 mol% dried under reduced pressure at 50 ° C. for 24 hours,
Ethylene-modified PV having a polymerization degree of 450 and a saponification degree of 98 mol%
A (abbreviated as PVA-1) powder 100 parts and okara powder 1
After mixing 00 parts and 100 parts of water, the mixture was melt-kneaded under the following conditions and pelletized. (Pelletizing conditions) Toyo Seiki Co., Ltd. Labo Plastomill twin screw 20 mmφ, L / D = 28, rotation speed 50
rpm motor 200V, rating 20A, molding machine temperature 120 ° C The pellets were injection molded at 120 ° C to obtain a molded product. The obtained molded product was allowed to stand for 7 days in an atmosphere of a relative humidity of 65% (20 ° C.) for humidity control, and various physical properties were evaluated by the following methods.

1) Flexural strength: measured according to JIS K7203. 2) Flexural modulus: measured according to JIS K7203. 3) Izod impact strength: Measured according to JIS K7110 (with notch). 4) Water resistance: immersed in water at 20 ° C for 24 hours, and observed for morphological changes. ：: Almost no resin was eluted, and the form was maintained. X: The resin elutes considerably and the form cannot be maintained when touched. 5) Dimensional change rate: 20 ° C, 65% R compared to immediately after molding
Measure the rate of change in length after standing at H for 7 days. 6) Natural disintegration: thickness 2 mm, length 10 cm, width 10 c
m was buried in the soil at a depth of 50 cm, and the form was observed. ：: After 6 months, there is a slight sign of morphological collapse,
After two months, the decomposition of more than 30% proceeds. ×: No change in morphology was observed at all even after 12 months.

Example 2 Pellets were obtained by melt-kneading in the same manner as in Example 1 except that apple pomace (powder) was used instead of the okara powder used in Example 1. The pellet was injection molded at 160 ° C., and the physical properties of the obtained molded product were evaluated. The results are shown in Table 1.

Example 3 Pellets were obtained by melting and kneading in the same manner as in Example 1 except that soy sauce pomace (powder) was used instead of the okara powder used in Example 1. The pellet was injection molded at 160 ° C., and the physical properties of the obtained molded product were evaluated. The results are shown in Table 1.

Example 4 Instead of PVA-1 used in Example 1, a polymerization degree of 600
Except for using unmodified PVA having a saponification degree of 97 mol% (abbreviated as PVA-2), the mixture was melt-kneaded in the same manner as in Example 1 to obtain pellets. The pellet was injection molded at 160 ° C. to obtain a molded product. The physical properties of the obtained molded product are also shown in Table 1.

Comparative Example 1 Except that only PVA-1 used in Example 1 was used, it was melt-kneaded in the same manner as in Example 1 to obtain a pellet. The pellet was injection molded at 220 ° C. to obtain a molded product. The physical properties of the obtained molded product are also shown in Table 1.

Comparative Example 2 To 100 parts of the PVA-1 powder used in Example 1, 900 parts of okara powder and 500 parts of water were added and melt-kneaded in the same manner as in Example 1 to obtain pellets. 160 pellets
Injection molding was performed at ℃ to obtain a molded product. The physical properties of the obtained molded product are also shown in Table 1.

Comparative Example 3 Commercially available polypropylene (MI = 2160 g, 230 ° C.)
30 g / 10 min) 100 parts and okara powder 100 parts for 20
The mixture was melt-kneaded at 0 ° C. to obtain pellets. Put these pellets in 2
Injection molding was performed at 00 ° C. to obtain a molded product. The physical properties of the obtained molded product are also shown in Table 1.

[0023]

[Table 1]

[0024]

Industrial Applicability The PVA-based resin composition of the present invention is excellent in mechanical strength and impact resistance, has good shape stability and dimensional stability, and has high hardness and rigidity and can be used for a wide range of applications. It is possible to obtain Further, the PVA-based resin composition of the present invention can provide a PVA-based resin composition having excellent natural disintegration properties.

Claims (5)

[Claims] 1. A polyvinyl alcohol resin (A) 10
A resin composition comprising 0 parts by weight and 3 to 500 parts by weight of an organic waste material (B). 2. The resin composition according to claim 1, wherein the polyvinyl alcohol resin (A) is a polyvinyl alcohol having a degree of polymerization of 200 to 5,000 and a degree of saponification of 90 to 100 mol%. 3. The method according to claim 1, wherein the polyvinyl alcohol resin (A) is α
-Containing 0.1 to 20 mol% of olefin units, and
The resin composition according to claim 1, having a degree of polymerization of 200 to 5000 and a degree of saponification of 90 to 100 mol%. 4. The organic waste material (B) is okara, coffee beans meal, malt cake, soy sauce cake, apple pomace, mandarin peel,
The polyvinyl alcohol resin composition according to claim 1, which is sludge or garbage. 5. A melt-formed product comprising the resin composition according to claim 1.