JP2001019819A - Polyvinyl alcohol resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyvinyl alcohol resin composition reduced in the tendency of the constituent polyvinyl alcohol to undergo thermal deterioration and improved in heat stability by mixing a polyvinyl alcohol with a triazole compound. SOLUTION: This composition is prepared by compounding 100 pts.wt. polyvinyl alcohol having a degree of polymerization of 100-2,000 with 0.1-10 pts.wt. triazole compound. The polyvinyl alcohol used may be one containing 1-20 mol% 4C or lower α-olefin such as ethylene, propylene, 1-butene, or isobutene or one containing 0.1-20 mol% alkyl vinyl ether or hydroxyalkyl vinyl ether with a 4C or lower alkyl. The polyvinyl alcohol resin composition may be one containing 100 pts.wt. polyvinyl alcohol resin, 0-300 pts.wt. organic or inorganie filler, 0-100 pts.wt. plasticizer, etc. Examples of processes for melt- molding the composition include compression molding, transfer molding, and extrusion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyvinyl alcohol resin composition comprising a polyvinyl alcohol (hereinafter abbreviated as PVA) polymer and a triazole compound.

[0002]

2. Description of the Related Art PVA is a typical water-soluble resin, and its dissolution rate varies depending on the degree of saponification, but has the property of dissolving in water to lose its shape. Also, PVA is known to be excellent in mechanical strength and a material superior to other resins, and is widely used as a fiber sizing agent, a film, and a coating agent for paper. Further PV
A is a biodegradable resin, and PVA dissolved in water.
Does not pollute the environment. By the way, PVA
When heat-treating and thermoforming, heat stability (coloring, odor, viscosity, etc.) is extremely important. In particular, with respect to melt molding, PVA is close to the crystal melting point and the decomposition start temperature, so that it is significantly deteriorated compared to polyethylene, polypropylene, polyvinyl chloride and the like, and has extremely low thermal stability. Therefore,
In order to easily melt-mold PVA, it is necessary to reduce the melting point by a method such as lowering the degree of saponification, copolymerizing ethylene, or adding a plasticizer or water. However, it is still not at a sufficient level, and such a method narrows the applicable range of the PVA used, such as the degree of saponification and the degree of modification. Factors that affect the thermal stability of PVA include the degree of polymerization, the degree of saponification, and the content of alkali metal salts. However, in practice, it is not clearly understood how these factors cause thermal degradation to proceed. Therefore, no effective method has been found for the remedy.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a PVA-based resin composition which suppresses thermal degradation of PVA with a specific additive and has excellent thermal stability.

[0004]

That is, the present invention provides a method for producing a polyvinyl alcohol (A) and a triazole compound (B).
Wherein the compounding ratio of the component (B) is 0.1 to 10 parts by weight with respect to 100 parts by weight of the component (A).
The above object has been achieved by a VA-based resin composition.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. In the composition of the present invention, a heat-meltable PVA-based resin is used as the component (A), which is obtained by saponifying a vinyl ester polymer. Examples of the vinyl ester include vinyl formate, vinyl acetate, vinyl propionate, and vinyl pivalate. Vinyl acetate is often used industrially.

The degree of polymerization and the degree of saponification of the PVA resin used in the present invention are not particularly limited. However, in consideration of the mechanical strength and morphological stability of the obtained molded product, and the viscosity stability during molding, those having a degree of polymerization of 100 to 2,000 are often used, and those having a polymerization degree of 200 to 1500 are preferable.
Similarly, the degree of saponification is preferably at least 40 mol%, more preferably at least 60 mol%.

The triazole compound of the component (B) used in the present invention has a triazole ring structure and includes 1,2,4-triazole and 3-amino-1,2,4-
Examples thereof include triazole, 4-amino-1,2,4-triazole and the like. In the composition of the present invention, the components
(A) The compounding ratio of the triazole compound of the component (B) to 100 parts by weight is 0.1 to 10 parts by weight,
-8 parts by weight is preferred, 0.4-6 parts by weight is more preferred, and 0.5-5 parts by weight is particularly preferred. When the compounding ratio of the triazole compound is less than 0.1 part by weight, the effect of the additive on thermal deterioration is not sufficient, and when the compounding ratio of the triazole compound is more than 10 parts by weight, the polymer melts. Thermal stability during molding is deteriorated, and decomposition and gelation are increased.

[0008] The PVA used in the present invention may contain α-olefins. They have 4 or less carbon atoms and include, for example, ethylene, propylene, 1-butene, isobutene, etc., and ethylene is more preferable in consideration of water resistance and hygroscopicity. The content of the α-olefin unit is 1 to 20 mol%, and when the content is more than 20 mol%, the solubility of the modified PVA in water decreases.

The PVA used in the present invention may contain an alkyl vinyl ether or a hydroxyalkyl vinyl ether. These have 4 or less carbon atoms in the alkyl group and include, for example, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether and the like. The content of these vinyl ethers is 0.1 to 20 mol%, and when the content is more than 20 mol%, the water solubility of PVA decreases.

In addition, as long as the effect of the present invention is not impaired, the PVA of the present invention may contain a vinyl alcohol unit,
It may contain a vinyl ester unit and a monomer unit other than α-olefins. Examples of such a unit include unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, (anhydride) phthalic acid, (anhydride) maleic acid, (anhydride) itaconic acid, or salts thereof, or alkyl esters having 1 to 18 carbon atoms. , Acrylamide, N having 1 to 18 carbon atoms
Acrylamides such as -alkylacrylamide, N, N-dimethylacrylamide, 2-acrylamidopropanesulfonic acid or a salt thereof, acrylamidopropyldimethylamine or an acid salt thereof or a quaternary salt thereof, methacrylamide, N- having 1 to 18 carbon atoms; Methacrylamides such as alkyl methacrylamide, N, N-dimethylmethacrylamide, 2-methacrylamidopropanesulfonic acid or a salt thereof, methacrylamidopropyldimethylamine or an acid salt thereof or a quaternary salt thereof, N-vinylpyrrolidone, N- N-vinylamides such as vinylformamide and N-vinylacetamide, vinyl cyanides such as acrylonitrile and methacrylonitrile, allyl acetate, propyl allyl ether, butyl allyl ether Le, allyl ethers such as hexyl allyl ether, vinyl chloride, vinylidene chloride,
Vinyl halides such as vinyl fluoride, vinylidene fluoride and vinyl bromide, vinyl silanes such as trimethoxy vinyl silane, monomers having an oxyalkylene group, isopropenyl acetate, 3-buten-1-ol, 4-pentene Hydroxy-containing α-olefins such as -1-ol, 5-hexen-1-ol, 7-octen-1-ol, 9-decen-1-ol and 3-methyl-3-buten-1-ol A, a monomer having a carboxyl group derived from fumaric acid, maleic acid, itaconic acid, maleic anhydride, phthalic anhydride, trimellitic anhydride or itaconic acid, ethylenesulfonic acid, allylsulfonic acid, methallylsulfonic acid, Monomers having a sulfonic acid group derived from 2-acrylamido-2-methylpropanesulfonic acid and the like, vinyloxy Ethyltrimethylammonium chloride, vinyloxybutyltrimethylammonium chloride, vinyloxyethyldimethylamine, vinyloxymethyldiethylamine, N-acrylamidomethyltrimethylammonium chloride, N-acrylamidoethyltrimethylammonium chloride, N-acrylamidodimethylamine, allyltrimethylammonium chloride, Examples include monomers having a cationic group derived from methallyltrimethylammonium chloride, dimethylallylamine, allylethyl and the like. Among these monomers, from the viewpoint of availability, copolymerizability and melt moldability, having allyl ethers such as allyl acetate, propyl allyl ether, butyl allyl ether, and hexyl allyl ether, and having an oxyalkylene group Monomer, 3
-Buten-1-ol, 4-penten-1-ol, 5
-Hexen-1-ol, 7-octen-1-ol,
9-decene-1-ol, 3-methyl-3-butene-1
And monomers derived from hydroxy group-containing α-olefins such as -ol. The content of these monomers is usually 20 mol% or less, preferably 10 mol% or less.

Examples of the polymerization method of the vinyl ester polymer include known methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. Among them, a bulk polymerization method or a solution polymerization method in which polymerization is performed without a solvent or in a solvent such as an alcohol is usually employed. Examples of the alcohol used as a solvent during the solution polymerization include lower alcohols such as methyl alcohol, ethyl alcohol, and propyl alcohol. As the initiator used for the polymerization,
For example, α, α′-azobisisobutyronitrile, 2,2
Known initiators such as azo initiators such as 2'-azobis (2,4-dimethylvaleronitrile, benzoyl peroxide, and n-propyl peroxycarbonate, and peroxide initiators. Although there is no particular limitation, a range of −30 to 150 ° C. is appropriate.

The vinyl ester polymer is saponified by a known method. For example, it is saponified while being dissolved in alcohol. Examples of the alcohol used for the saponification reaction include lower alcohols such as methyl alcohol and ethyl alcohol, and methyl alcohol is particularly preferably used. The alcohol used in the saponification reaction is 4
If it is 0% by weight or less, it may contain a solvent such as acetone, methyl acetate, ethyl acetate, and benzene. As a catalyst used for the saponification reaction, an alkali metal hydroxide such as potassium hydroxide or sodium hydroxide, an alkali catalyst such as sodium methylate, or an acid catalyst such as a mineral acid is used. The temperature of the saponification reaction is not particularly limited, but is preferably in the range of 20 to 60 ° C. When a gel-like product precipitates as the saponification reaction proceeds, the PVA polymer of the present invention is obtained by pulverizing the product at that time, washing and drying.

The PVA-based resin composition of the present invention may contain a filler, a plasticizer, another plastic resin, a fragrance, a coloring agent, a foaming agent, and a filler, as long as the object of the present invention is not impaired. Normally used for odorants, extenders, lubricants, release agents, ultraviolet absorbers, antioxidants, processing stabilizers, weathering stabilizers, antistatic agents, flame retardants, release agents, reinforcing materials, fungicides, preservatives, etc. Can be appropriately compounded. The filler is used to further increase the hardness and rigidity, give a sense of weight, adjust the speed of water disintegration and biodegradability, express anti-blocking properties, and provide printability. it can. As the filler, talc, clay, calcium carbonate, silica, mica, alumina, titanium oxide,
Examples include inorganic fillers such as zirconium oxide, boron nitride, and aluminum nitride, and organic fillers such as urea-formalin-based resin and melamine-formalin-based resin. The amount of the filler is not particularly limited, but is preferably 0 to 300 parts by weight, more preferably 0 to 100 parts by weight, based on 100 parts by weight of the PVA-based resin. The plasticizer has the effect of lowering the melting point, improving moldability, and imparting flexibility and toughness to the molded product. The plasticizer is not particularly limited, and those generally used as PVA plasticizers can be used. As this plasticizer,
Polyglycols such as glycerin, diglycerin and diethylene glycol, polyethers such as polyethylene glycol and polypropylene glycol, sorbitol and compounds obtained by adding ethylene oxide to a polyhydric alcohol such as glycerin, sugars, polyethers, bisphenol A, Phenol derivatives such as bisphenol S, other amide compounds such as N-methylpyrrolidone,
Compounds obtained by adding about 2 to 4 moles of an alkylene oxide to 1 mole of a trihydric or higher polyhydric alcohol, and water are further exemplified. The amount of the plasticizer is not particularly limited, but is preferably 0 to 100 parts by weight, more preferably 1 to 20 parts by weight, based on 100 parts by weight of the PVA-based resin. Further, as the other thermoplastic resin, for example, polyethylene,
General-purpose resins such as polypropylene, ABS resin, and polystyrene are exemplified.

The method for preparing the PVA-based resin composition of the present invention is not particularly limited, and a filler, a plasticizer, an additive, and the like may be simply added to the PVA-based resin. You may. Alternatively, the melt kneader may be kneaded and pelletized while separately charging a PVA-based resin, a filler, a plasticizer, an additive, and the like at a fixed ratio.

The method of melt-molding using the resin composition of the present invention is not particularly limited, and examples thereof include a compression molding method, a transfer molding method, a reinforced plastic molding method, an injection molding method, an extrusion molding method, and a method using a T-die. An extrusion film forming method, an inflation film forming method, a hollow forming method, a blow forming method, a calendar forming method, a foam forming method, a vacuum forming method, a pressure forming method, and the like are exemplified. If desired, another thermoplastic resin may be laminated. As the other thermoplastic resin, the same components as those exemplified above can be exemplified as desired components of the resin composition of the present invention.

[0016]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples. In the following Examples and Comparative Examples, “parts” and “%” mean on a weight basis unless otherwise specified. The degree of polymerization and the degree of saponification are determined by JISK
Measured according to 6726.

Example 1 Degree of polymerization: 500, degree of saponification: 98 mol%, ethylene modification amount: 8
2 parts by weight of a triazole-based aldehyde scavenger Chemcatch T-6900 manufactured by Otsuka Chemical Co., Ltd. were added to 100 parts by weight of polyvinyl alcohol (hereinafter referred to as PVA) powder which is mol%, and pellets were obtained by extrusion under the following conditions. Was manufactured. (Pelletizing conditions) Extruder: Labo Plastomill manufactured by Toyo Seiki Co., Ltd. Screw: Biaxial, same direction, 25 mmφ, L / D = 26 Screw rotation speed: 60 rpm Set temperature: 220 ° C. Discharge rate: 3.2 kg / h The thermal stability and moldability of the pellet were evaluated by the following methods. Table 2 shows the results. (1) Thermal stability Pellets are heat-treated and melted at 220 ° C. under a nitrogen atmosphere, and a part thereof is cooled to room temperature every hour, and gelation occurs by examining whether or not it is dissolved in DMSO. The time until was measured. (2) Moldability: Injection molding at 225 ° C ○: Molding was possible without any problem. Δ: Although moldable, there are problems such as irregular shapes. ×: Molding not possible (3) Flexural modulus Measured according to JIS K7203.

Examples 2 and 3 Pelletization and injection molding were carried out under the same conditions as in Example 1 except that the amount and type of the triazole-based aldehyde scavenger were changed. Table 2 shows the evaluation results.

Examples 4 to 8 Pelletization and injection molding were carried out under the same conditions as in Example 1 except that the degree of polymerization, saponification degree and modified species of PVA were changed. Table 2 shows the results.

Example 9 Chemcatch T was added to 100 parts by weight of PVA shown in Table 1.
After mixing 2 parts of -6900 and 20 parts of talc, pelletization and injection molding were performed under the same conditions as in Example 1.
Table 2 shows the evaluation results.

Example 10 Chemcat T was added to 100 parts by weight of PVA shown in Table 1.
After mixing 2 parts of -6900 and 10 parts of glycerin, pelletization and injection molding were performed under the same conditions as in Example 1. Table 2 shows the evaluation results.

Example 11 Chemcat T was added to 100 parts by weight of PVA shown in Table 1.
After mixing 2 parts of -6900 and 10 parts of water, pelletization and injection molding were performed under the same conditions as in Example 1. Table 2 shows the evaluation results.

Comparative Example 1 Using the PVA shown in Table 1, pelletization and injection molding were performed under the same conditions as in Example 1. Table 2 shows the evaluation results.

Comparative Examples 2 and 3 Pelletization and injection molding were performed under the same conditions as in Example 1 except that the amount of the triazole-based aldehyde scavenger was changed. Table 2 shows the evaluation results.

Example 12 PVA powder 1 having a degree of polymerization of 500 and a degree of saponification of 98 mol%
2 parts by weight of Chemcatch T-6900 was added to 00 parts by weight. Using this mixture, an aqueous solution is prepared so that the PVA concentration becomes 5 wt%, and the thickness is about 4 wt.
A 0 μm film was made. The obtained cast film was heat-treated in a hot-air dryer at 150 ° C. for 24 hours, and the coloring property at that time was evaluated. Table 3 shows the results.

Comparative Example 4 A heat treatment test was performed under the same conditions as in Example 14 using the PVAs shown in Table 1. Table 3 shows the evaluation results.

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

[Table 3]

[0030]

The present invention has made it possible to suppress deterioration during heat treatment and thermoforming by adding a triazole compound to PVA. By using such a PVA-based resin composition, a molded article can be stably manufactured.

Claims (4)

[Claims] 1. A composition comprising a polyvinyl alcohol (A) and a triazole compound (B), wherein the blending ratio of the component (B) is 0.1 to 10 parts by weight with respect to 100 parts by weight of the component (A). Polyvinyl alcohol-based resin composition. 2. The polyvinyl alcohol resin composition according to claim 1, wherein the polyvinyl alcohol (A) is a polyvinyl alcohol containing 1 to 20 mol% of an α-olefin having 4 or less carbon atoms. 3. The polyvinyl alcohol resin composition according to claim 2, wherein the α-olefin having 4 or less carbon atoms is ethylene. 4. The polyvinyl alcohol (A) may contain an alkyl vinyl ether or a hydroxyalkyl vinyl ether having an alkyl group having 4 or less carbon atoms in an amount of from 0.1 to 0.1.
The polyvinyl alcohol-based resin composition according to claim 1, which is a polyvinyl alcohol containing 20 mol%.