JPS5812301B2 - Polyvinyl alcohol cage - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a modified polyvinyl alcohol resin composition.

More specifically, it contains a microtype reaction product of polyhydric alcohol or alkanolamine and acrylic ester as a modifier, and has excellent flexibility. The present invention relates to a polyvinyl alcohol resin composition that can be heat-treated to give molded products with excellent water resistance.

Polyvinyl alcohol resin has tear strength and toughness. Because it has excellent properties such as oil resistance. It is widely used as a molding agent for films and sheets, as well as adhesives.

In these technical fields, plasticizers such as glycerin and diethylene glycol are added to resins for the purpose of imparting flexibility.

However, it is known that when such plasticizers are used for the purpose of imparting greater flexibility, the blocking resistance of the molded product deteriorates, and it is known that sweating occurs under high temperature and high humidity conditions. Since the pressure is relatively large, the plasticizer may escape during the molding process or over time, which has a major effect on the physical properties.

On the other hand, it is well known that polyvinyl alcohol resins themselves have problems with water resistance, and conventional methods for improving this, such as formalization, have been used. Benzalization, treatment with methylol urea or methylol melamine. Diisocyanate cross-linking, dialdehyde cross-linking, dicarboxylic acid cross-linking, carbamide cross-linking, etc. are known, but all of these require chemical treatment after molding, so they are difficult to handle, such as recovering chemicals and treating waste liquids. Often causes problems.

The present inventors are currently conducting extensive research into modifiers for polyvinyl alcohol resins, and have found that adding a micro-type reaction product of polyhydric alcohol or alkanolamine and acrylic ester to polyvinyl alcohol resins will reduce the change over time. A resin composition with low flexibility and excellent flexibility can be obtained. The present invention was completed based on the discovery that a molded product with significantly improved water resistance could be obtained by simply heating the resin composition after molding.

Below, the microtype reaction product of polyhydric alcohol or alkanolamine and acrylic ester used as a modifier in the present invention will be described in detail under G.

First, let us take polyhydric alcohol as an example and convert it to the general formula R(OH
) n (R: any organic residue, an integer of n≧2),
Acrylic acid ester is CH2=CHCOOR'(R':
When expressed as an alkyl group, a hydroxyalkyl group, or an alkoxyalkyl group), a modifying material can be synthesized by the reaction shown in the following formula.

That is. In such a reaction, mixtures of various reaction products can be obtained by appropriately selecting the molar ratio of acrylic acid ester and R(OH)n.

For example, if acrylic ester is used in an amount more than twice the amount of hydroxyl group GR of R(OH)n, a reaction product in which acrylic ester is added to most of the hydroxyl groups will be obtained, but when the reaction is carried out in equivalent amounts, Generally, a mixture of completely reacted products, partially reacted products, and small amounts of unreacted products are obtained.

The modifier used in the present invention has an average reaction rate of 50 mol% or more as shown by the following formula. Especially like L<c
63 to 96 mol% is used.

Average reaction rate - [(Number of moles of complete reactant × Number of functional groups] + Number of moles of C partial reactant × Number of reactive functional groups)] / (Number of moles of R(OH)n × n) + Specific examples of the polyhydric alcohols mentioned above Examples include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,4
-Butanediol. 1,5-pencundiol, 1,6
-Including alkanediols such as hexanediol. Alkyl-substituted diols such as 2-methyl-2-ethyl-1,3-propanediol and 2,22-dimethylpropanediol, diethylene glycol, etc. represented by the general formula HO-{CH2-CH20+TH (m: 2-20) Polyethylene glycols, furthermore, glycerin, l,1,1-i limethyloleecune, 1,1,1
-trimethylolpropane, 1,2,4-butanetriol, 3-methyl-1,3,5-pencunetriol,
Compounds containing polyfunctional hydroxyl groups such as 1,2,6-hexanetriol, penqueryslift, arabitol, and mannitol. Examples include glycols.

When alkanolamine is used, the reaction is, for example, HOCH2CH2NH2+3CH2-CHC00R'→
R'OOCCH2CH20CH2CH2N(C-2cI
As shown in 2C■■')2, the acrylic acid ester is added to the active hydrogen of both the hydroxyl group and the amino group in the form of a micromolecule.

Specific examples of alkanolamines include monoethanolamine, diethanolamine, triethanolamine, and various polyethylene glycols having a molecular weight of 1000 or less obtained by adding ethylene oxide to these alkanolamines.

On the other hand, specific examples of acrylic esters include methyl acrylate and ethyl acrylate. Including aliphatic lower alkyl substituents such as probyl acrylate and butyl acrylate, 2-hydroxyethyl acrylate-2 acrylate
Examples include hydroquine alkyl substituted products such as -hydroxybupyr, 3-hydroxybutyric acrylate, 4-hydroxybutyl acrylate, and alkoxyalkyl substituted products such as 2-ethoxyethyl acrylate. .

Polyvinyl alcohol resins to be modified in the present invention include fully saponified polyvinyl alcohol with a degree of saponification of 99 mol% or more, partially saponified polyvinyl alcohol, partially urethanized, partially acecooled, partially saponified polyvinyl alcohol, etc. Cyanethylation, partial hydroxyethylation. Part N,
Polyvinyl alcohol that has undergone modification such as N-dimethyl rubamoylethylation, or vinyl esters such as vinyl acetate and a small amount of other vinyl monomers. For example, ethylene, propylene, imbutylene. Allyl ester, impropenyl ester. It also includes saponified copolymers with vinyl ether, ethylene glycol monoallyl ether, etc.

The method of mixing the modifier and polyvinyl alcohol resin mentioned above is to mix the modifier directly. Method of impregnating resin.
Any method can be used, such as preparing a solution of the modifier using a suitable solvent, mixing this with the resin, and then removing the solvent.

The amount of modifier to be added can be any amount depending on the purpose, but for normal molding it is usually 3 to 30% (by weight) of the polyvinyl alcohol resin.

When molding using the resin composition of the present invention, if the stock solution is left in a solution or molten state at high temperature and for a long period of time or aged, gelation may occur and molding may become impossible. If the storage time is long, it is preferable to maintain the temperature at 100C or less.

When the molded product is heat-treated at 130 to 200°C for several seconds to several tens of minutes, intermolecular crosslinking easily occurs and the (hot) water resistance is significantly improved.

The resin composition of the present invention has properties that significantly improve water resistance (thermal) than that of force-heat treated GR without substantially impairing the inherent advantages of polyvinyl alcohol resins, so it can be used for food packaging films, self-crosslinking type glue. Fiber treatment agents, paper] Processing agents, paint base resins, gas impermeable membranes. Tank lining, hose. It is expected to have a wide range of applications, including belts and protective coatings for beverage containers.

The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples in any way.

Example 1 Performance evaluation was performed using modifiers obtained by the methods shown below (I) to (VD).

(I) Triethylene glycol A reaction product obtained by reacting three times the amount of methyl acrylate in the presence of sodium methylate with an average reaction rate of 96% (I) Triethylene glycol in the presence of sodium methylate A reaction product (I) with an average reaction rate of 85 mol obtained by reacting twice the amount of methyl acrylate was obtained by reacting glycerin with three times the amount of ethyl acrylate in the presence of sodium methylate. Reaction product (I) with an average reaction rate of 63. 1,4-butanediol was reacted with twice the amount of 2-hydroxyethyl acrylate in the presence of sodium ethylate.A reaction with an average reaction rate of 72 molar. Product (■) An average reaction rate of 92% obtained by reacting monoethanolamine with 4.5 times the amount of methyl acrylate using a trowel in the presence of sodium methylate. (V) Reaction product of diethanolamine with sodium methylate. Reaction products with an average reaction rate of 88% obtained by reacting 4 times the amount of methyl acrylate in the presence of It was added to an aqueous solution of polyvinyl alcohol (degree of polymerization 1700, degree of saponification 99.0 mol%) (the amount added was 10 parts of each modifier per 100 parts of polyvinyl alcohol), and then cast on a glass plate to give 20% °C.6
The film produced by controlling the humidity at 5% relative humidity had good flexibility, and had neither sweating nor blocking properties.

Next, 10 parts each of glycerin and dimethyl adipate were added to the polyvinylene recorder for the purpose of comparison with films to which each modifier had been added. Results of selecting a modified film and examining its solubility in hot water at 96°C after heat treatment at 150°C for 10 minutes. The results shown in Table 1 were obtained.

From the results in Table 1, it was confirmed that the water resistance of the resin composition of the present invention was significantly improved by heat treatment. Example 2 (I) was selected as the additive, and the following three types were selected as the polyvinyl alcohol resin. (1) Degree of polymerization: 1700. Partially saponified z-rivinyl encore with a degree of saponification of 88 mol (2) Fully saponified polyvinyl alcohol with a degree of polymerization of 1700, in which 5.1 mol% of the hydroxyl groups are converted to N,N-dimethyl-rubamoylethylated (3) Ethylene- Vinyl alcohol copolymer (ethylene content 7.2 mol, Ken C 99.5//%, degree of polymerization 1
500) Table 2 shows the properties of films prepared in the same manner as in Example 1 with different amounts of modifier added, and the hot water resistance after mouth heat treatment (150° C. for 10 minutes).

As is clear from the results in Table 2, the resin composition of the present invention has good flexibility. It is recognized that the hot water resistance due to heating is significantly improved.

Example 3 20 parts of modifier (I) was added to polyvinyl alcohol (polymerization degree 1
700, saponification degree 99 mol%), added a small amount of water and a surfactant, mixed at 70°C, and heated to 110°C.
It was extruded using a Koka type flow tester.

The meltability at this time was good, the extrudate was strong and highly flexible, and no sweating was observed.

The solubility of this extrudate in 96°C hot water was investigated with and without heat treatment at 150°C for 10 minutes. Those without heat treatment melted quickly, or those with heat treatment were almost insoluble.

still. The heat-treated molded products obtained in Examples 1 and 2.3 above were all toluene. It was insoluble in organic solvents such as benzene, and the inherent organic solvent resistance of polyvinyl alcohol resin was not impaired in any way.

Claims (1)

[Claims] 1. A polyvinyl alcohol resin composition containing a microtype reaction product of a polyhydric alcohol or an alkanolamine and an acrylic ester as a modifier.