JPH0551505A - Polyvinyl acetal composition - Google Patents

Abstract

PURPOSE:To obtain a polyvinyl acetal composition having excellent thermal stability by incorporating a specific compound into a polyvinyl acetal in a predetermined proportion. CONSTITUTION:The title composition comprises 100 pts.wt. polyvinyl acetal, e.g. polyvinyl butyral, and 0.01-3 pts.wt. compound represented by the formula (wherein R1 to R5 each is a 1-4C hydrocarbon group).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyvinyl acetal composition having excellent heat resistance stability.

[0002]

2. Description of the Related Art Conventionally, polyvinyl acetal is manufactured by acetalizing polyvinyl alcohol (hereinafter sometimes referred to as PVA) with an aldehyde, and is industrially used in applications such as paints, adhesives, and safety glass interlayer films. Widely used.

However, polyvinyl acetal has insufficient heat resistance stability, and there is a problem that its solution viscosity is lowered due to heat deterioration, and its particles, solutions, molded products and the like are colored.

Various methods have been proposed for improving these problems.

For example, a method of blending a compound represented by the following general formula (A) with polyvinyl acetal is disclosed in JP-A-54-1.
It is disclosed in Japanese Patent No. 25291.

[0006]

[Chemical 2] (In the above formula, R _{1 to} R ₄ each represent a hydrocarbon group having 1 to 4 carbon atoms.)

A method of blending a compound represented by the following general formula (B) or (C) with polyvinyl acetal is disclosed in JP-A-54-125292.

[0008]

[Chemical 3]

[Chemical 4] [In the above general formulas (B) and (C), R ₁₁ , R ₁₂ and R ₁₃
Are hydrogen or a hydrocarbon group having 1 to 4 carbon atoms, and R ₁₄ is a methyl group or an ethyl group. ]

However, the effect of improving heat resistance by these methods is insufficient in sustainability due to sublimation properties of the compound to be added, or the compound itself to be added forms a quinone structure to cause coloration. I am not satisfied with it.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above prior art, and an object thereof is to provide a polyvinyl acetal composition having excellent heat stability.

[0011]

As a result of various studies, the present inventor has found that a polyvinyl acetal composition containing a specific compound in polyvinyl acetal exhibits excellent heat resistance stability. Has been completed.

That is, the present invention provides a composition containing a polyvinyl acetal and a compound represented by the following general formula (I), wherein the compound represented by the following general formula (I) is added to 100 parts by weight of the polyvinyl acetal. Is contained in an amount of 0.01 to 3 parts by weight.

[0013]

[Chemical 5] (In the above formula, R _{1 to} R ₅ each represent a hydrocarbon group having 1 to 4 carbon atoms)

The present invention will be described in detail below.

As a specific example of the compound represented by the general formula (I) [hereinafter sometimes referred to as compound (I)] contained in the composition of the present invention, 4,4'-butylidene bis-
(6-t-butyl-3-methylphenol), 2,2 '
-Ethylidene bis- (4,6-di-t-butylphenol), 2,2'-iso-butylidene bis- (4,6-di-methylphenol) and the like, but among them, 2,
2'-Ethylidene bis- (4,6-di-t-butylphenol) is preferred.

The proportion of the polyvinyl acetal composition of the present invention containing the compound (I) is 10% by weight.
It is 0.01 to 3 parts by weight, preferably 0.02 to 2 parts by weight, based on 0 parts by weight. When the proportion is less than 0.01 parts by weight, the heat resistance stability of the polyvinyl acetal composition is not sufficiently improved, and when it exceeds 3 parts by weight, the polyvinyl acetal composition is easily colored by heating.

The polyvinyl acetal used for obtaining the composition of the present invention is not particularly limited, and any polyvinyl acetal can be used.

Polyvinyl acetal is obtained by using PVA as a raw material and acetalizing it with an aldehyde,
For example, it can be obtained in the form of powder or liquid. The polyvinyl acetal used in the present invention includes, in addition to the polyvinyl acetal obtained by saponifying a normal carboxylic acid vinyl ester polymer, an acetalized polyvinyl acetal, a raw material PVA.
As modified polyvinyl acetal obtained by using PVA modified by copolymerization, post-modification, etc., PVA with different modified, unmodified, average degree of polymerization, saponification degree, etc. is used as a raw material PVA. The obtained polyvinyl acetal and the like are also included. The raw material PVA is a complete polymer and copolymer of vinyl acetate and other fatty acid vinyl esters,
Alternatively, it is general to use a partially saponified polymer having an average degree of polymerization of about 200 to 4000.

The following methods (1), (2) and (3) are generally used for acetalizing PVA, but the method is not limited thereto. (1) Precipitation method: An aldehyde is added to a PVA aqueous solution in the presence of an acid catalyst to start an acetalization reaction. After that, a precipitate is formed as acetalization progresses, and thereafter the reaction proceeds in a heterogeneous system. (2) Dissolution method: PVA powder is suspended in a solvent of polyvinyl acetal, and aldehyde is added in the presence of an acid catalyst,
Start the acetalization reaction. With the progress of acetalization, the reaction product dissolves in the solvent, and then the reaction proceeds in a homogeneous system. (3) Homogeneous method: PVA aqueous solution in the presence of an acid catalyst is added with an aldehyde to start the acetalization reaction, and a polyvinyl acetal solvent that is compatible with water is added before the precipitation is formed to precipitate the precipitate. A method that promotes the reaction in a homogeneous system throughout the entire process, while preventing generation.

Aldehydes used in the reaction for acetalizing PVA include, for example, formaldehyde,
There are acetaldehyde, propionaldehyde, butyraldehyde, crotonaldehyde, benzaldehyde, etc., and one kind of aldehyde is used, or polyvinyl acetal obtained by using two or more kinds together in the reaction system for acetalization is also used in the present invention. be able to.
Upon completion of the acetalization reaction, the acid catalyst is generally neutralized with an alkaline substance, but it may be reacted with an alkylene oxide.

The method for obtaining the composition of the present invention is not particularly limited, and for example, the method of adding the compound (I) to the acetalization reaction system, the method of adding in the steps of precipitation / filtration / drying, these steps A method of adding to a powdery or granular polyvinyl acetal obtained through, a method of adding to a solution or emulsion of polyvinyl acetal, a coating containing polyvinyl acetal, a method of adding to an adhesive or the like, a solution of polyvinyl acetal used to obtain a molded article. Alternatively, there is a method of incorporating the compound into the compound, or a method of combining these. Among them, the method of adding the compound (I) to the acetalization reaction system and the method of adding the compound in the step after the completion of the acetal reaction and before the drying are already used in the heating and drying step for obtaining the polyvinyl acetal in the form of dry particles. It is preferable because it exerts an effect.

When the compound (I) is added to the polyvinyl acetal, if there is a loss of the compound (I) in the production process of the polyvinyl acetal, etc., the compound (I) is added to 100 parts by weight of the polyvinyl acetal in the resulting composition. The amount of the compound added is adjusted so that the content of I) is 0.01 to 3 parts by weight.

The compound (I) may be added to the polyvinyl acetal as it is, but it may be added with an aldehyde, a PVA aqueous solution,
It can be carried out by any method such as adding, blending by mixing, sprinkling, dipping or the like in a state of being dissolved or emulsified and dispersed in a medium for acetalization reaction, an organic solvent, a plasticizer or the like.

The composition of the present invention may contain various substances, and the substances to be mixed and contained are as follows:
For example, uncured or partially cured thermosetting resin (phenolic resin, amino resin, melamine resin, modified resin thereof, etc.), inorganic or organic filler (clay,
Talc, calcium carbonate, powdered silica, carbon black, carbon fiber, glass fiber, stone powder, zeolite, plastic powder that is not compatible with polyvinyl acetal, etc.), plasticizers, pigments (carbons, titanium oxide, basic) Zinc chromate-based compounds, etc.), stabilizers, catalysts, dyes, inorganic salts, surfactants, and the like. As the plasticizer, those usually used as plasticizers for plastics can be used, but in the polyvinyl butyral composition, an ester plasticizer having an ether bond in the molecule [triethylene glycol di-2-ethyl Butyrate, triethylene glycol di-2-ethylhexoate, di (butoxyethoxyethyl) adipate and the like] are preferred.

The proportions of various substances mixed and contained in the composition of the present invention can be arbitrarily selected according to the purpose.

[0026]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples. In the following, unless otherwise specified,
"Parts" and "%" indicate "parts by weight" and "% by weight", respectively.

Example 1 100 parts of PVA having an average degree of polymerization of 1700 and a saponification degree of 98.5 mol% was placed in a reaction vessel equipped with a temperature control and stirring device under stirring.
It was dissolved by heating in 900 parts of water. While continuing stirring, this aqueous solution was kept at 10 ° C., and 60 parts of 35% hydrochloric acid was added thereto. Then, 0.1 parts of 2,2'-ethylidene bis- (4,6-di-t-butylphenol) as compound (I) was dissolved in 57 parts of butyraldehyde, and the whole amount was continuously added and mixed for 30 minutes. .. Particles of polyvinyl butyral were produced 15 minutes after the start of the addition. Then, the reaction system was heated to 40 ° C. with stirring and kept at 40 ° C. for 4 hours. After the reaction was completed, an aqueous sodium hydroxide solution was added to neutralize the system, and the system was cooled to room temperature. Then, washing with water, filtration and drying were performed to obtain a white powdery polyvinyl butyral composition. The butyralization degree of polyvinyl butyral in the obtained composition was 76%.
Further, 2, in the obtained polyvinyl butyral composition
The content of 2'-ethylidene bis- (4,6-di-t-butylphenol) was 0.065 parts based on 100 parts of polyvinyl butyral. The viscosity stability showing the heat stability and the coloring stability of the obtained composition were measured, and the results are shown in Tables 1 and 2.

Example 2 As compound (I), 2,2'-ethylidene bis- (4,4)
0.05 part of 6-di-t-butylphenol) in the form of an anionic aqueous emulsion dispersion liquid having a content of about 50% is added to a PVA aqueous solution at 10 ° C under stirring in a reaction vessel, and 57 parts of butyraldehyde are added. A polyvinyl butyral composition was obtained in the same manner as in Example 1 except that was continuously added over 30 minutes. Tables 1 and 2 show the measurement results of the content of the compound (I), the viscosity stability, and the coloring stability of the obtained composition.

Example 3 As compound (I), 2,2'-ethylidene bis- (4,4)
A polyvinyl butyral composition was obtained in the same manner as in Example 1 except that the amount of 6-di-t-butylphenol) was changed to 0.03 part. Content of the compound (I) in the obtained composition,
The measurement results of viscosity stability and color stability are shown in Tables 1 and 2.

Example 4 As compound (I), 2,2'-ethylidene bis- (4,4)
A polyvinyl butyral composition was obtained in the same manner as in Example 1 except that the amount of 6-di-t-butylphenol) was 2.0 parts. Content of the compound (I) in the obtained composition,
The measurement results of viscosity stability and color stability are shown in Tables 1 and 2.

Example 5 As compound (I), 2,2'-ethylidene bis- (4,4 '
A polyvinyl butyral composition was obtained in the same manner as in Example 1 except that the amount of 6-di-t-butylphenol) was changed to 0.015 part. The results of measuring the content of the compound (I) and the viscosity stability of the obtained composition are shown in Tables 1 and 2.

Example 6 As compound (I), 2,2'-ethylidene bis- (4,
A polyvinyl butyral composition was obtained in the same manner as in Example 1 except that the amount of 6-di-t-butylphenol) was changed to 4 parts. Tables 1 and 2 show the measurement results of the content of the compound (I), the viscosity stability, and the coloring stability of the obtained composition.

Example 7 2,2'-ethylidene bis- (4,6-di-of Example 1)
4,4'-butylidenebis- (6-t-butyl-3) as compound (I) in place of 0.1 part of (t-butylphenol)
-Methylphenol) The polyvinyl butyral composition was obtained in the same manner as in Example 1 except that 0.1 part was used. Content of the compound (I) in the obtained composition, viscosity stability,
The measurement results of the coloring stability are shown in Tables 1 and 2.

Example 8 A mixed solution of 490 parts of methanol and 6 parts of 35% hydrochloric acid in a reaction vessel equipped with a temperature control and stirring device was stirred, while PVA 100 having an average polymerization degree of 2400 and a saponification degree of 98.5 mol% was added thereto. Parts were added. Then, 37 parts of acetaldehyde and 34 parts of butyraldehyde were added to the suspension of PVA particles under stirring, and the mixture was reacted at a temperature of 60 ° C. for 6 hours to obtain a methanol solution of polyvinyl acetal having acetoacetal units and butylacetal units. .. After completion of the reaction, the mixture was cooled, and an aqueous sodium hydroxide solution was added and mixed to neutralize the reaction liquid. Furthermore, 2,2'-ethylidene bis- (4,6-di-t-butylphenol) was added to the reaction solution as compound (I).
0.1 part was added and mixed. Water was added to this solution to precipitate particles, which were washed with water, filtered, and dried to obtain a polyvinyl acetal composition in the form of powder. The polyvinyl acetal in the obtained composition was vinyl acetate unit 1.9%, vinyl alcohol unit 16.4%, and the degree of acetalization 81.7% (the ratio of acetoacetal unit and butylacetal unit was a weight ratio measured by infrared absorption spectrum). 50:50). Content of the compound (I) in the obtained composition,
The results of viscosity stability and color stability are shown in Tables 1 and 2.

Example 9 PVA having an average degree of polymerization of 1700 and a degree of saponification of 98.5 mol% of Example 1
Instead of 100 parts, average polymerization degree of 2400, saponification degree of 99 mol%
PVA with 50 parts PVA, average polymerization degree of 500, and saponification degree of 98.5 mol%
Polyvinyl chloride was prepared in the same manner as in Example 1 except that 50 parts were used in combination and the amount of 2,2'-ethylidene bis- (4,6-di-t-butylphenol) used as the compound (I) was 0.2 parts. A butyral composition was obtained. The degree of butyralization of polyvinyl butyral in the obtained composition is 77%, 2,
The content of 2'-ethylidene bis- (4,6-di-t-butylphenol) was 0.13 parts based on 100 parts of polyvinyl butyral. The viscosity stability and color stability of the obtained composition were measured, and the results are shown in Tables 1 and 2.

COMPARATIVE EXAMPLE 1 2,6-di-t-butyl-phenol was used instead of 0.1 part of 2,2'-ethylidene bis- (4,6-di-t-butylphenol).
A polyvinyl butyral composition was obtained in the same manner as in Example 1 except that 0.1 part of para-cresol was used. Tables 1 and 2 show the measurement results of the content of 2,6-di-t-butyl-paracresol, the viscosity stability, and the coloring stability of the obtained composition.

Comparative Example 2 Instead of 2,2'-ethylidene bis- (4,6-di-t-butylphenol), 2,2'-methylenebis- (4-
A polyvinyl butyral composition was obtained in the same manner as in Example 1 except that 0.05 part of (methyl-6-t-butylphenol) was used. Tables 1 and 2 show the measurement results of 2,2'-methylenebis- (4-methyl-6-t-butylphenol) content, viscosity stability and color stability of the obtained composition.

Comparative Example 3 Polyvinyl butyral was obtained in the same manner as in Example 1 except that 2,2'-ethylidene bis- (4,6-di-t-butylphenol) was not used. Tables 1 and 2 show the measurement results of viscosity stability and coloring stability of the obtained polyvinyl butyral.

Comparative Example 4 A polyvinyl butyral composition was obtained in the same manner as in Example 1 except that the amount of 2,2'-ethylidene bis- (4,6-di-t-butylphenol) was changed to 0.005 part. .. Tables 1 and 2 show the measurement results of the content of the compound (I), the viscosity stability and the coloring stability of the obtained composition.

Comparative Example 5 Example 1 except that the amount of 2,2'-ethylidene bis- (4,6-di-t-butylphenol) was changed to 5.0 parts.
A polyvinyl butyral composition was obtained in the same manner as. Tables 1 and 2 show the measurement results of the content of the compound (I), the viscosity stability and the coloring stability of the obtained composition.

[0041] Examples 10 to 12 and Comparative Example 6 Ethanol / toluene (weight ratio _^1/1) in a mixed 900 parts of solvent,
100 parts of polyvinyl butyral obtained in Comparative Example 3 and 2,2'-ethylidene-bis- (4,6-
Di-t-butylphenol) was added in the amounts shown in Table 2 and mixed and dissolved. The obtained liquid was cast on a polyester sheet, air-dried, and then dried under reduced pressure at 20 ° C. to obtain a film-shaped molded product having a thickness of about 300 μm. This film was placed in a container and heated in an oven at 120 ° C for a predetermined number of days (2, 4, 6 days), then taken out and allowed to cool, and its surface color was measured by the method of measuring method 2 Color stability (2). Was measured for yellowness. The value of this degree of yellowness was used as the coloring stability of the molded product. The yellowness on day 0 is the measured value of the film before heating. The measurement results are shown in Table 3.

[0042]

[Table 1]

[0043]

[Table 2]

[0044]

[Table 3]

Measurement method

1. Viscosity Stability The polyvinyl acetal compositions and polyvinyl butyral obtained in each of the examples and comparative examples were used as samples and heated in an oven at 80 ° C. for a predetermined number of days (10, 30 days). Then, a mixed solvent of each sample after a predetermined number of days heating (ethanol / toluene = _^1/1, weight ratio) to prepare a 5% solution was dissolved, the viscosity using a B-type rotary viscometer at 20 ° C. of the solution Was measured. The 5% solution viscosity at 20 ° C. of the sample before heating was set to 0 days (before heating).

2. Coloring stability (1) Polyvinyl acetal compositions and polyvinyl butyral 100 mesh sieve pass products obtained in the respective Examples and Comparative Examples were used as samples, and the samples were placed in a container in an oven at 120 ° C. Heat for a predetermined number of days (2, 4, 6 days). After a predetermined number of days have passed, the sample is taken out of the oven and allowed to cool. (2) Next, colorimetric color difference meter (Z-1001 D manufactured by Nippon Denshoku Industries Co., Ltd.)
(P type), tristimulus values X, Y and Z of the surface color of the sample
Was measured, and the yellowness was calculated by the following formula. This value of yellowness indicates the coloring stability, and the smaller this value is, the lower the degree of coloring is and the better the coloring stability is. Yellowness = (100) (1.28X-1.06Z) / Y The yellowness 0 day is the yellowness measurement value of the powdery (100 mesh pass) sample before heating.

3. Content of Additive Substance The polyvinyl acetal composition obtained in each of the Examples and Comparative Examples was used as a sample, which was mixed solvent [ethanol / water =
_^9/1 (weight ratio)] dissolved liquid high performance liquid chromatography (Hitachi, L-4000 UV DETECTOR, ultraviolet absorbing
280nm, L-6000PUMP),
Quantification was performed by comparison with a calibration curve prepared in advance. The value obtained by the quantification was converted into the amount (part) with respect to 100 parts of the polyvinyl acetal in the composition, and made the content of the additive substance.

[0049]

As described above, the polyvinyl acetal composition of the present invention is excellent in heat stability without impairing the preferable properties of polyvinyl acetal.

Claims (1)

[Claims] 1. A composition containing a polyvinyl acetal and a compound represented by the following general formula (I): 0.01 to 3 parts by weight of the compound represented by the following general formula (I) per 100 parts by weight of the polyvinyl acetal. A polyvinyl acetal composition, characterized by containing parts by weight. [Chemical 1] (In the above formula, R _{1 to} R ₅ each represent a hydrocarbon group having 1 to 4 carbon atoms)