JPH05179217A - Adhesive composition - Google Patents

Abstract

PURPOSE:To provide an adhesive composition which contains a silane-grafted olefinic polymer as a base polymer, thus being suitably used as an adhesive for glass because of its high heat resistance and humidity resistance. CONSTITUTION:The subject adhesive composition is composed of 30 to 80 pts.wt. of a base polymer of a silane-grafted olefinic polymer and 20 to 70 pts.wt. of dispersed particles less than 80mum average size of propylene-alpha-olefin copolymer having 3.0 to 4.5 melt index at 95 deg.C.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an adhesive composition,
More specifically, the present invention relates to an adhesive composition that is suitable for a field that requires heat resistance, such as bonding glass and fixing components.

[0002]

2. Description of the Related Art Laminated glass for automobiles and the like is formed by sandwiching a plasticized resin sheet as an adhesive between two sheets of glass.
It is bonded by applying heat and pressure. The double glazing used for heat insulation and sound insulation is made by holding two sheets of glass with an intermediate air layer between them, adhering them to a spacer such as metal with an adhesive, and sealing the periphery with a sealing material. is there.

Glass has silanol (Si--O) on the surface.
H) group, so the adhesive for glass is also -OH
Polymers having polar groups such as groups, -COOH groups, -CO groups, -COOR groups have been used. The adhesive having these polar groups forms a hydrogen bond or a double bond with the silanol group on the glass surface to form a strong bond.

Conventionally, a method of graft-copolymerizing a silane compound with an olefin polymer has been known as a method of improving the adhesive strength to glass, metal and the like. For example, an adhesive in which an olefin polymer such as an ethylene-vinyl acetate copolymer (EVA) or an ethylene-ethyl acrylate copolymer (EEA) is grafted with a silane compound has been proposed (Japanese Patent Publication No. 26660/1990). , Special fair 2
-50147, JP-A-60-179483). These silane-grafted modified products react with silanol groups existing on the glass surface to exhibit high adhesive strength.

However, the adhesive having EVA or EEA as a base polymer has a melting point of about 6 of these polymers.
It is generally in the range of 0 to about 100 ° C. Therefore, when the surrounding environment temperature becomes 100 ° C. or higher after applying to an adherend such as glass and further force is applied, the adhesive softens and the adhesive force is lowered, which may cause inconvenience such as deviation. is there. Moreover, the adhesive strength of these adhesives decreases under high temperature and high humidity.

On the other hand, the photo-curing type adhesives do not easily slip after curing even at high temperatures, but since these adhesives are usually supplied in liquid form, they are difficult to handle, and further comparison is required. It is not suitable for filling a wide space.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an adhesive composition having improved adhesiveness at high temperature, heat distortion resistance and moisture resistance. Another object of the present invention is to provide an adhesive composition containing an olefin polymer grafted with a silane compound as a base polymer, which has excellent heat resistance and moisture resistance and is particularly suitable as an adhesive for glass.

The present inventor has conducted extensive studies in order to overcome the problems of the prior art. As a result, an olefin polymer such as EVA or EEA grafted with a silane compound is used as a base polymer, and a propylene-α olefin copolymer is added to the base polymer. By blending and dispersing the propylene-α-olefin copolymer so as to form a fine dispersed phase, without impairing the adhesiveness of the base polymer, adhesiveness at high temperature, heat distortion resistance, It has been found that the moisture resistance can be improved. The present invention has been completed based on these findings.

[0009]

According to the present invention, 190 to 30 parts by weight of a base polymer composed of an olefin polymer grafted with a silane compound is added to 190 parts by weight of the base polymer.
Propylene- [alpha] olefin copolymers 20 to 7 having a melt index of 3.0 to 4.5 measured at 0 [deg.] C.
There is provided an adhesive composition characterized in that 0 part by weight forms a dispersed phase having an average particle size of 80 μm or less.

The present invention will be described in detail below. Examples of the olefin polymer grafted with the silane compound include ethylene-ethylene-vinyl acetate copolymer and the like.
Vinyl ester copolymers; ethylene-ethyl acrylate copolymers, ethylene-butyl acrylate copolymers, ethylene-methyl methacrylate copolymers and other ethylene-unsaturated carboxylic acid ester copolymers; ethylene-butene copolymers And a glycidyl group-containing olefin polymer such as an ethylene-vinyl acetate-glycidyl methacrylate copolymer or an ethylene-ethyl acrylate-glycidyl acrylate copolymer.

Among these, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, glycidyl group-containing olefin-based polymer and the like are preferable. When the glycidyl group-containing olefin polymer is adhered at a high temperature, the adherend reacts with the epoxy group derived from the glycidyl group to improve the adhesive strength. Further, these silane-grafted modified products can be used alone or in combination of two or more kinds.

Examples of the silane compound include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (β-methoxyethoxy) silane, vinyltriacetoxysilane, acryloxypropyltrimethoxysilane and methacryloxypropyltrimethoxysilane. Saturated alkoxysilane compounds are mentioned.

The method of graft copolymerizing the silane compound is not particularly limited, but a method of melt mixing the olefin polymer and the silane compound in the presence of a radical polymerization initiator by a conventional method is preferable. The graft amount of the silane compound is usually about 0.2 to 4 parts by weight with respect to 100 parts by weight of the olefin polymer.

In the present invention, the melt index at 190 ° C. is 3.0 to 4.5 in the base polymer composed of the olefin polymer grafted with the silane compound.
The propylene-α olefin copolymer within the range is mixed and dispersed. In this case, the propylene-α-olefin copolymer is mixed and dispersed so as to form a dispersed phase having an average particle diameter of 80 μm or less in the base polymer.

Usually, the propylene-α-olefin copolymer preferably has a melting point in the range of 120 to 160 ° C. When the propylene-α-olefin copolymer is mixed and dispersed in the base polymer so as to form a fine dispersed phase, the propylene-α-olefin copolymer is heated even in the vicinity of the melting point of the base polymer.
Since the melting of the α-olefin copolymer does not begin, the effect as if the filler was filled is exhibited, and the thermal deformation of the entire adhesive composition is suppressed.

The propylene-α-olefin copolymer is a propylene-α-olefin having 4 to 20 carbon atoms (for example, 4
-Methyl-1-pentene, 1-decene, 1-hexene,
1-butene).
The composition is 10 to 85 mol% of propylene and 9 of α-olefin.
It is generally in the range of 0 to 15 mol%. As a specific example, propylene 10 to 85 mol%, 1-butene 3
.About.60 mol%, and other α-olefins of 10 to 85 mol%.

By the way, generally, in the field of polymer blends, many studies have been conducted on the relationship between the dispersion state of compatible and incompatible systems and the physical properties. However,
Regarding the relationship between the dispersion state and the specific physical properties when a specific polymer and another polymer are blended, there is no means other than concretely confirming by experiments.

For example, as the polymer having a melting point of 120 ° C. or higher, there are various polymers such as polyethylene and polyester elastomer in addition to the propylene-α-olefin copolymer, but these polymers have no adhesiveness to glass or the like. is there. Therefore, when these high melting point polymers are dispersed in a base polymer made of an olefin polymer grafted with a silane compound, the heat deformability is improved to some extent, but the adhesiveness originally possessed by the base polymer is reduced. It is desirable that the heat deformability and the adhesiveness at high temperature be improved without deteriorating the adhesiveness originally possessed by the base polymer.

The present inventor conducted various studies on various polymers and found that the propylene having a melt index (MI) measured at 190 ° C. in the range of 3.0 to 4.5.
When the α-olefin copolymer is mixed and dispersed in the base polymer so as to form a dispersed phase having an average particle size of 80 μm or less, the heat deformability is remarkably improved, the adhesive strength at high temperature is good, and the moisture resistance is high. I found that it is also excellent in sex.

Even with a propylene-α-olefin copolymer, a polymer having an MI outside the above range cannot achieve the purpose. That is, even if MI is less than 3.0,
If it exceeds 4.5, the MI of the entire composition is affected, and it becomes unsuitable as an adhesive. If the MI of the adhesive composition is too small, it will not flow easily and lacks in filling properties, leading to a decrease in adhesive strength. Conversely, if it is too large, the amount of adhesive that will flow out will be large and the amount of adhesive that remains in the necessary areas will be small Will be polluted.

The mixing ratio of both in the adhesive composition is 80: base polymer to propylene-α-olefin copolymer.
It is within the range of / 20 to 30/70 (weight ratio). If the ratio of the silane compound graft polymer as the base polymer is more than this range, a sufficient heat distortion temperature cannot be obtained,
On the other hand, if the proportion of the propylene-α-olefin copolymer exceeds this range, sufficient adhesive force cannot be obtained.

The silane compound graft polymer and the propylene-α-olefin copolymer are incompatible with each other, and the dispersion state of both has a great influence on the properties as an adhesive and the heat deformability. In the present invention, the silane compound graft polymer is used as a base polymer, and the propylene-α-olefin copolymer has an average particle size of 80 μm or less in the base polymer.
Preferably, they are mixed and dispersed so as to form a dispersed phase of 30 μm or less.

In order to make the diameter of the dispersed phase of the propylene-α-olefin copolymer 80 μm or less, the mixing conditions of both polymers are important. For example, when the propylene-α-olefin copolymer is mixed with a two-roll roll for about 10 minutes at a temperature slightly lower than the melting point of the propylene-α-olefin copolymer, the propylene-α-olefin copolymer is dispersed in the silane compound-grafted polymer. The average size of the dispersed phase composed of coalesces is 100.
It becomes about μm. The composition thus obtained is very brittle, and if it is formed into a sheet having a thickness of 2 mm, whitening or cracking occurs when it is bent. On the other hand, propylene-
When mixed with a twin roll or a biaxial mixer at a temperature higher than the melting point of the α-olefin copolymer by 5 to 10 ° C. or more, the diameter of the dispersed phase composed of the copolymer is 80 μm or less at the maximum. Further, the smaller the diameter of the dispersed phase, the higher the thermal deformability, and when the sheet is formed into a sheet, the whitening and cracks due to bending can be reduced to a level at which it does not matter. From these examination results, the diameter of the dispersed phase composed of the propylene-α olefin copolymer is preferably 30 μm.
m or less.

The adhesive composition of the present invention comprises propylene-α
When it is heated above the melting point of the olefin copolymer, it exhibits good flowability, and the adhesive strength to glass can be maintained at the same level as the adhesive strength of the silane compound graft polymer alone. It is considered that this is because when contacting with glass, the silane compound graft polymer having an affinity for glass is oriented on the glass surface, and the propylene-α-olefin copolymer forms a domain inside thereof.

Another important property of the adhesive composition of the present invention is moisture resistance. Generally, the adhesive strength of an adhesive to glass decreases when exposed to high temperature and high humidity,
In the adhesive composition of the present invention, since the dispersed phase composed of the hydrophobic propylene-α-olefin copolymer is present in the composition, it can be expected that the permeation of moisture can be suppressed. The change in adhesive strength after standing for 1 week in an environment of ° C and humidity of 95% is superior to that of the silane compound graft polymer alone. This is symmetrical with the fact that the adhesive force is significantly reduced in the addition system such as polyethylene or polyester elastomer.

[0026]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[Examples 1 to 5, Comparative Examples 1 to 6] As an adhesive for glass, a melting point of 92 ° C, a glass transition temperature of 45 ° C, M
Using the silane compound graft EVA of I4.5, propylene-α olefin copolymer, polyester elastomer or high density polyethylene (HDPE) was mixed in the mixing ratio shown in Table 1, and the mixture was mixed with a twin roll or a twin screw mixer. Kneading was performed for 10 minutes under the temperature conditions shown in Table 1 to obtain an adhesive composition. The physical properties of the obtained adhesive composition were evaluated, and the results are shown in Table 1.

The methods for measuring the physical properties are as follows. <Thermal deformation starting temperature (TMA)> 10 to 85 mol% A sheet having a thickness of 1 mm was prepared using each adhesive composition, and 15 g was applied by a Shimadzu TMA measuring machine at a heating rate of 10 ° C / min. , And the deformation starting temperature was measured.

<Adhesiveness> Two pieces of glass 20 mm × 10
Using an adhesive composition sheet piece cut into a size of mm, the sheet was pressed and bonded at 190 ° C., and the shear peeling force was measured. The pulling speed at this time was 50 mm / min.

<Moisture resistance> Similarly to the above, a test piece obtained by laminating two pieces of glass was placed in a constant temperature and humidity chamber of 90 ° C. × 95% for 1 week, and the shear peeling force was measured. <Appearance of Sheet> The adhesive (composition) sheet was bent at 180 ° and its appearance was judged. <Diameter of dispersed phase> The diameter of the dispersed phase was measured by observing a sample obtained by thinly slicing the composition with an optical microscope.

The polymers in Table 1 are as follows. (* 1) Propylene-α olefin copolymer: melting point 15
2 ° C., MI (190 ° C.) 4.0 (* 2) propylene-α olefin copolymer: melting point 14
1 ° C, MI (190 ° C) 1.7 (* 3) polyester elastomer: melting point 170 ° C (* 4) HDPE: melting point 132 ° C

[0032]

[Table 1]

As is clear from Table 1, the adhesive composition of the present invention is excellent in adhesive strength at high temperature, heat distortion temperature and moisture resistance.

[0034]

EFFECTS OF THE INVENTION According to the present invention, there is provided an adhesive composition having excellent adhesive strength at high temperature, heat deformability and moisture resistance. The adhesive composition of the present invention is particularly suitable for fields in which it is required to bond glass plates and hold glass components with high accuracy under high temperature and high humidity.

Claims (2)

[Claims] 1. A melt index, measured at 190 ° C., of 3.0 to 80 parts by weight in a base polymer of 30 to 80 parts by weight of an olefin polymer grafted with a silane compound.
An adhesive composition characterized in that 20 to 70 parts by weight of a propylene-α-olefin copolymer in the range of 4.5 form a dispersed phase having an average particle size of 80 μm or less. 2. An olefin polymer grafted with a silane compound is at least one selected from the group consisting of an ethylene-vinyl acetate copolymer, an ethylene-ethyl acrylate copolymer, and a glycidyl group-containing olefin polymer.
The adhesive composition according to claim 1, which is a silane-grafted modified product of one kind of olefin polymer.