JPH068329A - Adhesive for thermoplastic resin member and joining method used thereof - Google Patents

Abstract

PURPOSE:To obtain an adhesive for thermoplastic resin member to which a high frequency adhesive method is applicable by allowing a conductive compound to be contained in an inorganic solvent that softens the thermoplastic resin member. CONSTITUTION:An inorganic solvent used herein is of the type that it can evenly soften the joined surfaces and thus generates a combination between both the surfaces to be joined with only slight pressure. For a conductive compound, a low molecular weight compound is used that has no reaction with an inorganic solvent used here and has conductivity and, in particular, e.g. water, lower alcohol and the like having an OH group is used. A mixture of the inorganic solvent and conductive compound is applied on at least one joined surface of two thermoplastic member, and thereafter they are brought into press contact with each other and, when high frequency voltage is applied on the adhesive, the solvent can be dried in a short time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive for joining a thermoplastic resin member used for forming a frame such as a frame, a door frame and a gasket, and a joining method using the adhesive.

[0002]

2. Description of the Related Art Frames such as frames and door frames are generally formed by joining rod-shaped or plate-shaped thermoplastic resin members with an adhesive. After joining, it is aesthetically preferable that the joining surfaces of the thermoplastic resin members are integrated,
Generally, as the adhesive, a solvent adhesive that softens the joint surface of the thermoplastic resin member and fuses both joint surfaces is used.

For example, when joining vinyl chloride plate-like materials, an organic solvent such as methyl ethyl ketone or tetrahydrofuran that softens vinyl chloride is applied to the joining surfaces, and then the joining surfaces are pressed against each other and at a predetermined joining angle. , So that the vinyl chloride plates are pressed together.
When left standing in this state, the organic solvent present between the joint surfaces is volatilized and solidified, and both joint surfaces softened by the organic solvent are fused and integrated by pressure.

[0004]

In the above method, the solvent intervening between the joint surfaces is completely volatilized, and the thermoplastic resin member and the joint angle are pressed so as not to deform until the joint surfaces are fused and integrated. It is necessary to leave it in the state. However, it takes about one day on average until the solvent is completely evaporated, and it takes about one week depending on the type of the solvent, so that there is a problem in that the storage place is troubled.

Further, when the drying time of the solvent becomes long, the thermoplastic resin member is softened to the inside and the joint portion swells, and on the other hand, the coating amount of the solvent as an adhesive is reduced in order to shorten the drying time, If a quick-drying solvent is used, there is a problem that the bonding strength becomes insufficient. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an adhesive for thermoplastic resin members that can utilize a high-frequency adhesive method and a joint that can be easily joined in a short time using the adhesive. To provide a method.

[0006]

The adhesive for thermoplastic resin members of the present invention is characterized by containing an organic solvent and a conductive compound for softening the thermoplastic resin member. The joining method using the adhesive for thermoplastic resin member of the present invention,
The adhesive for a thermoplastic resin member of the present invention is applied to the joint surface of at least one of the two thermoplastic resin members,
It is characterized in that the thermoplastic resin members are pressed against each other and a high frequency voltage is applied between both joint surfaces.

[0007]

EXAMPLES Organic solvents used in adhesives for thermoplastic resin members generally have sufficient activity to soften the entire joint surface evenly and to an appropriate depth, and lightly press both joint surfaces together. It is preferable that the bonding be caused between the bonding surfaces by itself, and that the evaporation rate is faster. Specifically, alicyclic compounds such as cyclohexane; low molecular weight ketones such as cyclohexanone and methyl ethyl ketone; aromatic compounds such as benzene, toluene, xylene; esters of lower carboxylic acids such as ethyl acetate; tetrahydrofuran, dioxane, etc. Cyclic ethers are used. The above organic solvents may be used alone or in combination of two or more. The organic solvent is appropriately selected depending on the type of thermoplastic resin member to be joined. In the selection, the solubility parameter (SP value) can be used as an index, and an organic solvent having a value close to the solubility parameter value of the thermoplastic resin member to be joined may be selected.

As the conductive compound, a low molecular compound which does not react with the organic solvent used for the adhesive and has conductivity, particularly a low molecular compound having an OH group is used. For example, water; lower alcohols such as methanol and ethanol; lower dihydric alcohols such as ethylene glycol and diethylene glycol; lower carboxylic acids such as acetic acid. Of these conductive compounds, those suitable for the type of solvent are appropriately selected.

The content of the conductive compound in the adhesive is
It may be an amount necessary and sufficient for imparting conductivity to the adhesive, and generally, an amount of about 1 to 30% by weight is preferable. The adhesive for thermoplastic resin of the present invention is a mixture of the organic solvent and the conductive compound. When a conductive compound is mixed with an organic solvent, it may be separated or may be in a stable dispersion state depending on the difference in SP value of each substance.
The adhesive of the present invention may be in a separated state or a stable emulsion state. In some cases, a stable emulsion adhesive can be obtained simply by shaking, by stirring with a homomixer, or by adding a surfactant that does not react with any of the organic solvent and conductive compound. In some cases. on the other hand,
When the adhesive in a separated state is used, it is necessary to shake or stir the adhesive to uniformly disperse the conductive compound in the organic solvent.

The composition of the adhesive for thermoplastic resin members of the present invention is appropriately determined according to the type of the thermoplastic resin members to be joined so as to have the above constitution. Since the adhesive of the present invention has conductivity, it generates heat when a high frequency voltage is applied to the adhesive. By utilizing such a property, it is possible to instantly terminate the adhesion even with the use of a solvent which conventionally takes about one day to dry.

The adhesive of the present invention is a member which is generally an amorphous thermoplastic resin which is easily soluble in an organic solvent, such as polyvinyl chloride (PVC), acrylonitrile-butadiene-styrene (ABS) resin, polystyrene or the like. For joining
Especially useful. Next, a bonding method using the thermoplastic resin adhesive of the present invention will be described with reference to FIGS. 1 and 2.

Attempt to join by the bonding method of the present invention 2
The two thermoplastic resin members 1 and 2 may be different types of thermoplastic resin members as long as they are a combination (a combination having a close SP value) that dissolves in the organic solvent in the adhesive, but the point of fusion bonding integration Therefore, it is preferable to use members made of the same kind of thermoplastic resin. First, the adhesive for thermoplastic resin members of the present invention is uniformly applied to the joint surfaces 1a, 2a of the thermoplastic resin members 1, 2 having a substantially fan-shaped cross section. The application amount is appropriately selected depending on the size of the thermoplastic resin member to be joined, the type of resin, etc., but is generally an amount that can be uniformly applied to the surfaces.

An adhesive 2 is applied to the joint surfaces 1a, 2a.
The two members 1 and 2 are sandwiched between elongated pressing copper plates 3a and 3b each having an L-shaped cross section and flat sandwiching plates 4a and 4b. The sandwiching plates 4a, 4b can be slid vertically,
The members 1 and 2 are pressed from above to press the copper plates 3a and 3 for pressing.
It can be fixed to b. Pressurizing copper plates 3a, 3
b is the pressing direction of the joint surface (indicated by a white arrow in the figure)
It is slidably attached to the high frequency adhesive device. When the pressing copper plates 3a and 3b are slid and the joining surfaces of the sandwiched members 1 and 2 are brought together, a predetermined joining angle (for example, 90 °) is obtained at a portion where the joining surfaces are joined (hereinafter referred to as a joining portion). Can be formed.

The pressing copper plates 3a and 3b are joined to the joint surfaces 1a and 2a.
The member 1 and the member 2 are pressed against each other by sliding in the pressurizing direction. The joint portion is indicated by 6, and the joint surface 1a and the joint surface 2a
An adhesive agent 7 is interposed between and. Then, the joint 6
So as to be sandwiched between the pressurizing copper plates 3a and 3b.
The copper plate 5 for electrodes is arranged on the upper surface of the. The electrode copper plate 5 is connected to the anode (or cathode) of the high frequency power source, and the pressing copper plate 3a,
3b is connected to a cathode (or an anode), and a high frequency voltage is applied between the electrode copper plate 5 and the pressing copper plates 3a and 3b. Since the conductive compound is uniformly dispersed in the adhesive 7, the application of the high frequency voltage makes the molecular movement of the conductive compound vigorous, and the adhesive 7 generates heat due to friction between the molecules. As a result, the temperature of the joint portion 6 rises, and the volatilization of the organic solvent in the adhesive 7 is promoted. On the other hand, the joint surfaces 1a and 2a are
It is softened by the organic solvent in the adhesive and is fused and integrated by pressure fixing. The heat generation of the adhesive 7 due to the application of the high frequency voltage also promotes the softening and integration of the two joint surfaces 1a and 2a.

In the joint portion thus joined, the members are integrated, and no bulge, burr or the like remains at the joint portion.
Therefore, by applying the joining method of the present invention to joining a soft plastic material such as a gasket, which has been conventionally joined by heat sealing, deburring after heat sealing becomes unnecessary. [Specific Example] VR2 (trade name) manufactured by Konishi Co., Ltd. was used as an organic solvent for softening vinyl chloride. 10
100 g of water was added to 00 g of VR2 and stirred by a homomixer to prepare a stable emulsion adhesive for polyvinyl chloride. VR2 is a mixture of 45 to 55% by weight of methyl ethyl ketone, 25 to 35% by weight of cyclohexanone, and 5 to 15% by weight of tetrahydrofuran.

The adhesive for polyvinyl chloride prepared above was applied to both joint surfaces of two polyvinyl chloride members each having a substantially fan-shaped cross section. Then, as shown in FIG. 1, two polyvinyl chloride members are sandwiched between a copper plate for pressing and a copper plate for sandwiching, and they are pressed against each other so as to form a bonding angle of 90 °. Pinched and fixed with. The copper plate for pressure and the copper plate for electrodes are
They are connected to the cathode and anode of the high frequency power supply, respectively.
In this state, a high frequency voltage with an output of 3.5 kw was applied to the joint for 5 seconds. For high frequency bonding, a high frequency heating device MCY ₃ (trade name) for woodworking machines manufactured by Yamamoto Vinita was used. When both members were removed from the apparatus, the joint was fusion-bonded and integrated, and the joining was completed. When the joint was cut and observed, it was confirmed that the joint was sufficiently satisfactory with the destruction of the members.

An adhesive prepared by mixing 50 g of methanol in place of water was prepared, and the same procedure as above was carried out. As a result, the joint was fusion-bonded and integrated, and the joint was completed. there were. On the other hand, instead of the adhesive for thermoplastic resin of the present invention, only VR2 was applied to the joint surface, and it was attempted to adhere with the high frequency heating device in the same manner as above. No heat was generated and the joint surface did not solidify. Therefore, if the material is left still in a pressure-fixed state as in the prior art, it took a whole day and night to completely solidify the joint.

As can be seen from the above, even if the conventional solvent adhesive is used, the thermoplastic resin member cannot be bonded at high frequency.
However, when the adhesive for thermoplastic resin of the present invention is used, high-frequency bonding becomes possible, and the time until joining and integration can be shortened.

[0019]

EFFECT OF THE INVENTION The adhesive for thermoplastic resin of the present invention is an adhesive which has conductivity and generates heat when a high frequency voltage is applied. Therefore, by adhering the thermoplastic resin member using the adhesive of the present invention, the solvent can be dried in a short time by applying a high frequency voltage to the joint. Therefore, unlike the conventional case, it is not necessary to store the resin until it solidifies while maintaining a predetermined bonding angle, and the bonding work can be automated.

Further, since the members joined together by the joining method of the present invention are integrated and no bulges or burrs are left on the joining parts, it is suitable for joining in the field where joining has conventionally been performed by heat sealing or the like. When the joining method of the present invention is applied, deburring after heat sealing is unnecessary, and the work after joining is simplified.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a bonding method of the present invention.

FIG. 2 is a diagram for explaining the bonding method of the present invention.

[Explanation of symbols]

 1 Thermoplastic Resin Member 1a Bonding Surface 2 Thermoplastic Resin Member 2a Bonding Surface 3 Copper Plate for Pressing 5 Copper Plate for Electrode 6 Bonding Part 7 Adhesive

[Procedure amendment]

[Submission date] August 18, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction content]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive for joining a thermoplastic resin member used for forming a frame such as a frame or a door frame , and a joining method using the adhesive.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

[Specific Example] VR2 (trade name) manufactured by Konishi Co., Ltd. was used as an organic solvent for softening vinyl chloride. 100 g of water was added to 1000 g of VR2, and the mixture was stirred with a homomixer to prepare a stable emulsion adhesive for polyvinyl chloride. VR2 is 45 to 55% by weight of methyl ethyl ketone, cyclohexanone 2
A mixture of 5 to 35% by weight and tetrahydrofuran 5 to 15% by weight.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Delete

Claims (4)

[Claims] 1. An adhesive for a thermoplastic resin member, comprising an organic solvent for softening the thermoplastic resin member and a conductive compound. 2. The adhesive for a thermoplastic resin member according to claim 1, wherein the conductive compound is a low molecular weight compound containing an OH group. 3. The adhesive for a thermoplastic resin member according to claim 1, wherein the concentration of the conductive compound in the organic solvent is 1 to 30% by weight. 4. The adhesive for a thermoplastic resin member according to any one of claims 1 to 3 is applied to the joint surface of at least one of the two thermoplastic resin members, and the thermoplastic resin members are bonded to each other. A joining method using an adhesive for a thermoplastic resin member, which comprises press-contacting and applying a high-frequency voltage to the adhesive interposed between both joining surfaces.