JPH0791520B2 - Adhesive and method for adhering polypropylene with different polar materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a polypropylene-based synthetic resin molded product without surface treatment and without using a primer, and metal such as iron and aluminum, ceramic, animal or plant property. The present invention relates to an adhesive capable of adhering to a product made of a heterogeneous material having a polarity such as a synthetic resin having a polarity other than fibrous material and a polyolefin, in particular, an adhesive having excellent heat resistance and an adhesion method using the adhesive. It is applied to automobiles, home appliances, audio equipment, etc., which are used in large quantities and are used not only plainly but also in combination with other materials. Also, corrosion resistance,
It can also be applied to a laminated material of polypropylene and a metal plate such as a steel plate or an aluminum plate, which is used for damping or as a lightweight structural material.

[Conventional technology]

Polypropylene is non-polar, does not easily dissolve in a solvent, and is difficult to bond. Various adhesives are commercially available that can bond polypropylenes to each other without using a primer, but they are not effective for bonding metals such as iron and aluminum, glass, ceramics, and other polar materials.

In order to bond polypropylene and the different materials having the polarity, the surface of the polypropylene molded article to be adhered was improved by corona discharge, flame, plasma or the like, or surface treatment with a chromic acid / sulfuric acid mixture. Then, use a commercially available epoxy adhesive, cyanoacrylate adhesive, or the like, or modify polypropylene by adding a filler such as wood powder or talc and / or an elastomer, and then apply a primer to the modified polypropylene. After that, a method of applying a commercially available adhesive, adhesion with a dedicated hot melt agent, and the like have been performed. Recently, special adhesives for polyolefins that use a special primer have been put on the market.

In a laminated material with a metal plate, a modified polyolefin resin by graft or random copolymerization using an organic acid having a double bond or an anhydride thereof as a comonomer is used instead of an ordinary synthetic resin.

[Problems to be solved by the invention]

In surface modification by pretreatment, there are problems such as shape limitation for corona discharge treatment, size limitation for plasma treatment and expensive equipment, flame treatment has dangers due to use of fire, etc. Since the activity is lost in this case, there is a common problem that it is difficult to handle the object to be treated.

Chemical treatment requires the use of chemicals that are sources of pollution and special treatment tanks.

Further, hot melt cannot be applied as it is to the whole surface adhesion such as a laminated material. The price of special adhesives is high, and there is a price limitation such as the need for a primer coating process. In addition, the resin modification method has problems of changes in physical properties and high price of raw material resin. In the case of a laminated material that is adhered during melt extrusion, it is difficult and in some cases impossible to devise a method for providing a space in the resin layer of the multilayer laminated material or the vibration damping material.

As described above, it is not advantageous to use polypropylene because the unit price of resin is low when bonding different types of polar materials to plastic.

Therefore, polypropylene is not used when adhering a plastic and a dissimilar material except when polypropylene is required in terms of physical properties.

[Means for solving problems]

As a means for solving the above problems, the present inventor has invented the adhesive and the bonding method of Japanese Patent Application No. 61-242840 as a result of various studies.

That is, the invention of this Japanese Patent Application No. 61-242840 shows that low-chlorinated polypropylene has adhesiveness to polypropylene,
Not only has it been clarified that highly chlorinated polyolefin and chlorinated rubber have adhesiveness to different polar materials such as iron pieces, and that the mixture of both adheres polypropylene and different polar materials, the adhesive strength , It is due to the discovery that it is stronger than the adhesive strength shown between the respective materials, but in the method of the present invention, since the high chlorinated compound is used on the metal surface side, rust may occur around the bonded portion. There is.

The present inventor has variously studied a composition which does not contain a high chlorinated product and can obtain a high adhesive force, and a novolac of a para-position-substituted alkylphenol is compatible with chloroprene, which is a highly chlorinated polyolefin which is a component of the present invention. It was also found that polypropylene and a heterogeneous material having polarity are adhered to each other when the solution B substituted with chlorinated rubber and the solution A of the present invention are used together. Furthermore, when heating while maintaining the crimped state,
It was found that the adhesive strength is approximately doubled, and that the adhesive strength of the adhesive of Japanese Patent Application No. 61-242840 at the time of heat bonding can be obtained.

As a result of various studies based on the above findings, the adhesive and the bonding method of the present invention were completed.

That is, the first invention of the present invention comprises the following compositions as non-volatile components, respectively: A liquid chloroprene and low chlorinated polypropylene having a chlorine content of 35% by weight or less B liquid chloroprene and alkyl having 2 or more carbon atoms A group of one or more novolaks starting from a phenol selected from the group consisting of para-position substituted phenols and terpene phenols Selected from the group consisting of aromatic hydrocarbon solvents and chlorinated hydrocarbon solvents Liquid containing one or more kinds of mixed solvent or a mixed solvent of these solvents as a main component with another solvent, which are separately stored, and are composed of the solutions A and B stored separately. The gist is an adhesive characterized by its properties.

In the second invention, when the above-mentioned A / B2 liquid is used for adhesion, the A liquid is applied to the adhered surface of the polypropylene molded product, and the B liquid is applied to the adhered surface of the heterogeneous material product having polarity. The gist is a bonding method characterized in that both coated surfaces are overlapped and pressure-bonded.

Further, a third aspect of the present invention is, when the adhesive agent of the present invention is used for adhesion, irrespective of the application method, after the application surfaces are overlapped with each other, heating and drying are performed while maintaining the pressure-bonded state. To do.

[Action]

The adhesive of the first invention exhibits adhesiveness to polypropylene or to a material that is completely different from polypropylene such as metal and glass, and is therefore a heterogeneous material having a different polarity from polypropylene, which is theoretically difficult. Can be bonded without a primer, and the bonding strength between the two materials of the same kind is high, and when the method of heating during bonding which is the third invention is applied, it is considered to be the most difficult to bond. Adhesion strength between unmodified polypropylene homopolymer and stainless steel plate or glass doubled to 50kg
reaches / cm ² . However, in the bonding of polypropylenes and the bonding of stainless steel plates, the increase in bonding strength due to heating is extremely small.

Further, in the bonding method of the second invention, the mixing of the liquids A and B2 can be omitted in the bonding, and the bonding strength equivalent to that when the two liquids are mixed and used can be obtained.

As described above, the reason why the adhesive of the present invention exerts a large adhesive strength between different kinds of materials having different polarities than that of the same kind of materials is that the polar group of the molecule constituting the adhesive is the polar material side. It is thought to be oriented to. That is, as a result of this orientation, polar groups are unevenly distributed on the adhesive surface of the adhesive layer on the polar material side, and the polypropylene side surface is made more nonpolar to increase the adhesive strength with polypropylene, and the adhesive strength by heating is increased. This is explained by the fact that the orientation is promoted by the active molecular motion and the uneven distribution of polar groups is increased. Since such polar group orientation does not occur between similar materials, the effect of heating is small.

The details will be described below.

Chloroprene, which is one of the non-volatile components in the liquid A, serves as a base material of the adhesive of the present invention, and it is solid at room temperature to maintain cohesive force. Low-chlorinated polypropylene, which is another non-volatile component, imparts adhesiveness to polypropylene, and the chlorine content was limited to 35% by weight or less. Because it is extremely scarce. As an example of the low chlorinated polypropylene, the chlorine content is 8 to 30.
Weight percent isotactic polypropylene can be used. When the chlorine content of the low chlorinated isotactic polypropylene is 8% by weight or less, the solubility in a solvent and the compatibility with other components are significantly reduced, and it is difficult to commercialize it.

Low chlorinated polypropylene is a low chlorinated compound of atactic polypropylene and isotactic polypropylene.
There is a seed, and the latter is excellent in heat resistance, but it is said that it is difficult to apply it to an adhesive due to its poor solubility and compatibility, but the present invention separates each poorly compatible resin into By adopting the adhesive method in which the B2 solution is used and mixed or separated at the time of use, and then the coated surfaces are overlapped, it can be used as an adhesive component and an adhesive having excellent heat resistance can be obtained.

Further, the preferable mixing ratio of chloroprene and low chlorinated polypropylene is 60 to 90% by weight of chloroprene and 40 to 10% by weight of low chlorinated polypropylene, and when exceeding this range,
The adhesive strength when the polypropylene is adhered to each other with only the liquid A is lowered. Particularly preferred ranges are 70 to 80% by weight of chloroprene and 20 to 30% by weight of low chlorinated polypropylene.

The novolak in the liquid B imparts adhesiveness to different polar materials such as metal and glass, and is a para-position-substituted phenol having an alkyl group having 2 or more carbon atoms, such as parapropylphenol, parabutylphenol, paraoctylphenol, It is one kind or a mixture of one or more kinds of novolak obtained by condensing a phenol selected from the group consisting of paranonylphenol and isomers thereof and terpene phenol alone with formaldehyde under an acidic catalyst. Preferred novolaks are para-t-butylphenol, novolaks obtained from terpenephenols or mixtures of both. The raw material phenol of novolak was limited to para-position-substituted alkylphenols and terpene phenols, in the case of other phenols, it did not condense in a chain form, and the obtained novolak was soluble in a solvent,
This is because the compatibility with chloroprene is poor.

The solvent is one kind or a mixed solvent of one or more kinds selected from the group consisting of an aromatic hydrocarbon solvent and a chlorinated hydrocarbon solvent, or a mixed solvent with another solvent containing these solvents as a main component. The reason is that although there are other solvents such as a ketone type and an ester type as a solvent for dissolving the non-volatile components of the liquids A and B, a solvent containing them as a main component cannot provide sufficient adhesive strength. .

Aromatic hydrocarbon-based and chlorinated hydrocarbon-based solvents are effective because they have the property of swelling or slightly dissolving polypropylene. Among these solvents, preferred are toluene, kylene, trichloroethylene, tetrachloroethylene, chlorocyclohexane and the like. Further, the addition of a stabilizer used for vinyl chloride resin or the like is preferable because it improves heat aging resistance and hot water resistance.

The adhesive of the present invention is a polypropylene homopolymer, a copolymer of propylene and ethylene or other α-olefins, a modified resin containing these as the main components, and a composite material containing various fillers. It can be applied to adhesion of various polypropylenes.

When the adhesive of the present invention is used to adhere to polypropylene and a different material having polarity, the method of the present invention uses the solution A to the adhered surface of the polypropylene molded product and the solution B to the adhered surface of the dissimilar material product. Although it is said that they are applied to each other, and then they are laminated and pressure-bonded, the solution A and the solution B may be mixed well just before use without applying this method, and they may be layered and pressure-bonded after application. The preferred ratio of use or mixing of solution A and solution B is 3: 7 to 5: 5.

However, in any method, in order to obtain sufficient adhesive strength, it is necessary to heat in a crimped state, the heating conditions are 100 ℃ or more, preferably 120 ~ 130 ℃, the heating time is 5 to 15 minutes. is there. Bonding strength is 50-100% by this heating
Increase.

〔The invention's effect〕

As described above, the adhesive of the present invention enables the theoretically difficult adhesion of polypropylene and a completely different material having polarity, such as metal and glass, without a primer. The application range of the combination use with different materials having

Moreover, the adhesive of the present invention can be prepared with a combination of commercially available materials without using a special material, and since it is separated into the A and B2 liquids, the dissolution and mixing operations for preparing each liquid are easy,
That is, not only is it easy to manufacture, but the method of applying each liquid to the adhered surfaces of the respective materials and superposing and pressing them without mixing the liquids A and B at the time of bonding requires an expensive mixing device. Without doing so, the work is easy, the same adhesive strength as when using a mixer is obtained, and there is no troublesome handling when normally using a two-component type.

That is, the present invention provides an economically advantageous adhesive and an adhesive method. Combined with the above, the present invention is extremely significant industrially.

Specific examples of the effects of the present invention will be shown by the following examples.

〔Example〕

Liquid A having a composition ratio shown in Table 1 below and liquid B having a composition ratio shown in Table 2 were prepared.

Liquid A was added to a predetermined amount of 20 wt% toluene solution of low chlorinated polypropylene with 4 times the predetermined amount of chloroprene, diluted with stirring, and diluted with chloroprene.
Prepare by stirring for 24 hours.

Solution B was prepared by completely dissolving a predetermined amount of novolac in a predetermined amount of toluene, then adding a predetermined amount of chloroprene, allowing it to stand for 24 hours and then stirring it.

Use the solutions A and B that have been prepared for 1 week or more after preparation, and use JIS K-6850 according to the test piece and the bonding method described below.
An adhesive test piece was prepared by a method according to (Tensile of adhesive, Shear adhesive strength test method), and a tensile test was performed.

Polypropylene: Polypropylene homopolymer (Mitsui Noblene JHH-G) and polypropylene block copolymer (Mitsui Noblene BJHH-G), size 70 x 12.5 x
2mm injection-molded sheet punched product Dissimilar material: stainless steel (SUS 430), dimensions 70 × 25 × 0.
8mm glass (microscope slide glass), dimensions 76 × 26 × 1.2mm nylon 6 (Toray nylon: Amilan CM1017), nylon 66 (Toray nylon: Amilan CM3006), dimensions 88 ×
24 x 2 mm injection-molded sheet cut piece Adhesion method After degreasing the adherend surface of the test piece with isopropyl alcohol for polypropylene and glass and with toluene for metal piece and nylon, adhesion was performed by the following two methods.

1. Separation coating method Liquid A is applied to the former adhered surface of both polypropylene and dissimilar material test pieces, and liquid B is applied to the latter adhered surface using a paste brush, and both coated surfaces are overlapped. Combine and clip it from both sides with two clips (Kokuyo double clip, mid-clear 34) and fix it by crimping.

2. Mixed coating method Immediately before the adhesion test, both liquids A and B are weighed in equal amounts, mixed, and sufficiently stirred to apply the mixed liquid to the adhered surfaces of both polypropylene and dissimilar material test pieces with a poster brush. Then, both coated surfaces are crimped and fixed with clips as described above.

The adhesive test material crimped and fixed with a clip obtained by the above method was measured after removing the clip after 24 hours and after 48 hours in the case of feeling at room temperature.

In the case of feeling of heating, after leaving it for 1 hour, it was put in a hot air circulation type oven heated to a predetermined temperature, taken out after a predetermined time and allowed to cool, and after cooling, the clip was removed, and it was left standing for 24 hours at room temperature and then measured.

Table 3 shows the tensile strength measurement results. The numerical value of the adhesive strength is the average value of the measured values of the three materials.

Claims (6)

[Claims] 1. A non-volatile component containing the following composition, respectively, and one or more mixed solvents selected from the group consisting of aromatic hydrocarbon solvents and chlorinated hydrocarbon solvents, or A polypropylene having a two-component property and composed of a liquid A and a liquid B, which are separately stored and have a mixed solvent of these solvents as a main component with another solvent, and a heterogeneous material having polarity. adhesive. Liquid A Chloroprene and low-chlorinated polypropylene with a chlorine content of 35% by weight or less Liquid B Chloroprene and a novolak starting material from a phenol selected from the group consisting of para-position-substituted phenols having 2 or more carbon atoms and terpene phenol One kind or a mixture of one or more kinds 2. The polypropylene according to claim 1, wherein the low-chlorinated polypropylene contained in the liquid A is a chlorinated product of isotactic polypropylene having a chlorine content of 8 to 30% by weight. Adhesive with different polar materials. 3. The polypropylene according to claim 1, wherein the novolac contained in the liquid B is a novolac of a phenol of either para-t-butylphenol or a terpene phenol or a mixture of both novolaks. Adhesive with different materials with polarity. 4. The adhesive of polypropylene according to claim 1, wherein the non-volatile component in each of the liquids A and B has the following composition: Non-volatile composition of liquid A Chloroprene 70 to 90% by weight
And a low chlorinated product of isotactic polypropylene having a chlorine content of 8 to 30% by weight and 30 to 10% by weight. A non-volatile component composition of the liquid B. Chloroprene 50 to 90% by weight.
And 10 to 50% by weight of a novolak starting from one of para-t-butylphenol and terpenephenol or a mixture of both. 5. A non-volatile component containing one of the following compositions, one or more solvents selected from the group consisting of aromatic hydrocarbon solvents and chlorinated hydrocarbon solvents, or When using a two-component adhesive composed of separately stored liquid A and liquid B, which contains a mixed solvent of these solvents as a main component with another solvent, liquid A, chloroprene and chlorine Low chlorinated polypropylene B liquid with an amount of 35% by weight or less One or more novolaks starting from a phenol selected from the group consisting of chloroprene and para-position-substituted phenols having 2 or more carbon atoms and terpene phenols Mixture A is applied to the adhered surface of polypropylene molded product, and liquid B is applied to the adhered surface of products of different materials having polarity, and both applied surfaces are overlapped. A method of adhering polypropylene and a different material having polarity, which is characterized in that they are pressure-bonded together. 6. One or a mixture of one or more solvents selected from the group consisting of aromatic hydrocarbon solvents and chlorinated hydrocarbon solvents, each containing the following composition as a non-volatile component: When using a two-component adhesive composed of separately stored liquid A and liquid B, which contains a mixed solvent of these solvents as a main component with another solvent, liquid A, chloroprene and chlorine Low chlorinated polypropylene B liquid with an amount of 35% by weight or less One or more novolaks starting from a phenol selected from the group consisting of chloroprene and para-position-substituted phenols having 2 or more carbon atoms and terpene phenols Mixture of solution A and solution B are mixed when used and applied and pressure-bonded to the surface to be adhered, or solution A is applied to the surface to be adhered of polypropylene molded product and solution B is polar. A method for adhering polypropylene with a heterogeneous material having polarity, which is characterized in that the respective surfaces to be adhered of a different material product are applied, the applied surfaces are overlapped and pressure-bonded, and then heating is performed while maintaining the pressure-bonded state.