JPH0684258B2 - Low self-adhesive interlayer film for laminated glass - Google Patents

Description

TECHNICAL FIELD The present invention relates to an interlayer film for laminated glass having reduced self-adhesiveness.

(Prior Art) As an interlayer film for laminated glass, plasticized polyvinyl butyral obtained by adding a plasticizer to polyvinyl butyral is widely known, and is widely used for automobiles, aircrafts, and constructions. However, since the conventional interlayer film for laminated glass has strong adhesiveness on the film surface, there is a problem that the film surface adheres to itself (self-adhesion) during storage or transportation.
In order to prevent this self-adhesion, conventionally, the film surface is embossed,
Further, an anti-sticking agent such as sodium bicarbonate was sprayed. Therefore, a water washing step for removing the anti-adhesive agent and a drying step for adjusting the water content of the intermediate film after that are necessary.

(Problems to be Solved by the Invention) An object of the present invention is to provide a plasticized polyvinyl acetal interlayer film which has low tackiness and therefore does not require the above-mentioned industrially disadvantageous steps.

(Means for Solving Problems) The low self-adhesive interlayer film for laminated glass of the present invention is formed by adding a plasticizer to polyvinyl acetal obtained by acetalizing polyvinyl alcohol with an aldehyde having 6 to 10 carbon atoms. It is a thing.

The average degree of polymerization of the polyvinyl alcohol used in the present invention is preferably 800 to 3000, and its saponification degree is preferably 95 mol% or more in order to obtain an intermediate film having good transparency.

6 carbon atoms that can be condensed with the polyvinyl alcohol
As preferable examples of the aldehyde of 10 to 10, n-hexyl aldehyde, n-heptyl aldehyde, n-octyl aldehyde, 2-ethyl-hexyl aldehyde, n-nonyl aldehyde, n-decyl aldehyde and the like can be mentioned. Alternatively, they are used in appropriate combination. As shown in FIG. 1, n of C8 is obtained in that an interlayer film having low self-adhesiveness can be obtained.
-Octyl aldehyde and 2-ethyl-hexyl aldehyde are particularly preferably used.

In order to obtain a polyvinyl acetal acetalized with an aldehyde having 6 to 10 carbon atoms, a conventionally known method for producing polyvinyl acetal can be adopted.

For example, in the precipitation method, polyvinyl alcohol has 6 carbon atoms.
One or more aldehydes of 10 to 10 are added and reacted to obtain a precipitate at a relatively low temperature, and then the reaction system is aged at room temperature, neutralized, washed with water and dried.

The polyvinyl acetal used in the present invention may be acetalized with an aldehyde having a carbon number of 6 to 10 and an aldehyde having a carbon number of 6 to 10 within a range capable of achieving the object of the present invention. However, the proportion (% by weight) of aldehydes other than C6-10 consumed by acetalization is preferably lower than that of C6-10 aldehydes.

If the degree of acetalization of the polyvinyl acetal used in the present invention is too low, the compatibility with the plasticizer becomes poor,
If it is too high, various physical properties such as penetration resistance in laminated glass are deteriorated, so 60 to 75 mol% is desirable. The degree of acetalization is measured by a known method such as the hydroxylamine hydrochloride method.

As the plasticizer used in the present invention, those used in general polyvinyl butyral are widely used, and examples thereof include triethylene glycol-di-2-ethylbutyrate and triethylene glycol-di-2-ethylhexoate. Is preferably used. The amount of plasticizer added is preferably 20 to 60 parts by weight with respect to 100 parts by weight of polyvinyl acetal. This is because if the amount of the plasticizer is too small, the penetration resistance decreases, and if it is too large, the plasticizer bleeds out, that is, oozes out to the film surface, which adversely affects the transparency and adhesiveness of the laminated glass.

The interlayer film of the present invention has extremely low self-adhesiveness under atmospheric temperature conditions (generally 50 ° C. or lower, preferably 40 ° C. or lower) as shown in the following examples. On the other hand, it is possible to provide a laminated glass which has excellent adhesion to glass and excellent impact resistance under the processing conditions for processing laminated glass by heating and pressing.

(Examples) Examples of the present invention will be shown below.

The self-adhesion was measured as follows. A plasticizer is added to the polyvinyl acetal resin, mixed, kneaded with a 4-inch roll at 80 ° C. for 5 minutes, and then pressed at 150 ° C. for 30 minutes to form a uniform film having a thickness of 0.7 mm. Cut two 2cm x 1cm samples from this film and stack them together for 12
Apply a load of 5g and leave it in a high temperature and high humidity tank. Temperature and humidity conditions are 60 ° C for 2 hours, and accelerated evaluation is performed. This condition corresponds to storage at 40 ° C for 2 months. This sample is subjected to T-type peeling at 28 ° C. at a speed of 34 mm / min to measure the self-adhesive force.

When the self-adhesive force is 0.5 kg / cm or less, harmful permanent deformation does not occur even if a part of the interlayer film formed into a wound body or a stacked body is unwound or peeled from another part, which is convenient. is there.

Example 1 Polyvinyl alcohol having a polymerization degree of 1400 and a saponification degree of 98 mol%
163.4 g was added to 2977.5 g of distilled water and dissolved while stirring at 80 ° C. for 3 hours. Then, the temperature of this system was gradually lowered, and 50 g of 35% hydrochloric acid was added at 38 ° C. Then, 2-ethylhexyl aldehyde was added at 28 ° C. at 19.9 g and 2 ° C. at 139 g. The reaction system was kept at 2 ° C. and precipitation occurred in 2 hours. After adding 150 g of 35% hydrochloric acid to the system, the temperature was raised and the mixture was aged at 25 ° C. for 4 hours. Then, by a conventional method, the reaction system is neutralized with sodium hydroxide, and the resin is washed with water and dried to give polyvinyl-2.
A powder of ethylhexanal was obtained. The degree of acetalization of this resin was 60 mol%.

38 parts by weight of triethylene glycol-di-2-ethylbutyrate as a plasticizer was added to 100 parts by weight of this polyvinyl-2-ethylhexanal to prepare a sample for self-adhesion test as described above, and self-adhesion was performed by T-type peeling The adhesion force was measured. As a result, the peeling force was 0.17 kg / cm (see Table 1).

Examples 2 to 3 Polyvinyl-2-ethylhexanal resin obtained in the same manner as in Example 1 was mixed with triethylene glycol-di-2-
33 parts by weight (Example 2) and 28 parts by weight (Example 3) of ethyl butyrate were added, and the T-type peeling force was measured as described above. The results are shown in Table 1.

Examples 4 to 6 Polyvinyl alcohol was dissolved with stirring in the same manner as in Example 1, and the temperature of the reaction system was lowered to 50 g of 35% hydrochloric acid at 38 ° C.
added. A mixed aldehyde of 2-ethylhexyl aldehyde and n-octyl aldehyde at a molar ratio of 1: 1 at 28 ° C.
19.9 g and 139.2 g were added at 2 ° C. Keep the reaction system at 2 ℃,
After a precipitate was obtained in 2 hours, 150 g of 35% hydrochloric acid was added, the temperature was raised to 25 ° C., and the mixture was aged for 4 hours. Then, the mixture was neutralized, washed with water and dried to obtain a polyvinyl mixed acetal. The degree of acetalization is
It was 60 mol%. This polyvinyl mixed acetal 100
38, 33, 28 parts by weight of triethylene glycol-di-2-ethylbutyrate were added to each part by weight, and the T-type peeling force was measured as described above.

Examples 7 and 8 Polyvinyl alcohol was dissolved with stirring in the same manner as in Example 1, and n-decylaldehyde and n-hexylaldehyde were added to the reaction system. The addition temperature of hydrochloric acid and aldehyde is based on Example 1. After aging, the corresponding polyvinyl acetal was obtained by neutralization, washing with water and drying. The degree of acetalization was 60 mol% in all cases.
38 parts by weight of triethylene glycol-di-2-ethylbutyrate was added to 100 parts by weight of these acetals, and the T-type peeling force was measured as described above. The results are shown in Table 1.

Comparative Examples 1 and 2 After dissolving polyvinyl alcohol in the same manner as in Example 1, hydrochloric acid was added while the temperature was lowered, and 11.1 g and 77.7 g of n-butyraldehyde were added at 28 ° C. and 2 ° C., respectively. After obtaining the precipitate, it was aged at 25 ° C. for 4 hours, neutralized, washed with water and dried to obtain polyvinyl butyral. Acetalization degree is 60
It was mol%. Triethylene glycol-di-
2-Ethyl butyrate was mixed and the T-type peel force was determined as described above. The results are shown in Table 1.

Comparative Example 3 In the same manner as in Example 1, polyvinyl alcohol was dissolved with stirring, and n-dodecylaldehyde was added to the reaction system to obtain a precipitate. The polyvinyl acetal obtained by aging, neutralization, washing with water and drying in the same manner as in Example 1 had an acetalization degree of 60 mol%. Triethylene glycol-di-2-ethylbutyrate was mixed with this, and the T-type peeling force was determined according to the above. The results are shown in Table 1.

(Effects of the Invention) The interlayer film for laminated glass of the present invention has adhesiveness to glass equal to or higher than that of conventional plasticized polyvinyl butyral interlayer films, and can provide a laminated glass having impact resistance, Since the tackiness is extremely low, it is not necessary to spray an anti-tacking agent.

Therefore, it does not require various steps such as a washing step for removing the anti-adhesive agent and a subsequent drying step in production, and thus has a high industrial value.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the relationship between the self-adhesive force of the interlayer film and the carbon number of the aldehyde used in Examples (1, 4, 7, and 8) of the present invention and Comparative Examples (1 and 3).

Claims (3)

[Claims] 1. A low self-adhesive interlayer film for laminated glass, which is obtained by adding a plasticizer to polyvinyl acetal obtained by acetalizing polyvinyl alcohol with an aldehyde having 6 to 10 carbon atoms. 2. A first acetalization degree of 60 to 75 mol%.
The interlayer film according to the item. 3. The amount of plasticizer added is 10% polyvinyl acetal.
The interlayer film according to item 1 or 2, which is 20 to 60 parts by weight with respect to 0 parts by weight.