JPH058230B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a thermoplastic heat-resistant adhesive. More specifically, the present invention relates to a thermoplastic heat-resistant adhesive that has practically sufficient adhesive strength even in the high temperature range of 150 to 200°C. Conventionally, the mainstream of heat-resistant adhesives has been those based on thermosetting heat-resistant resins such as epoxy resins or phenolic resins, and recently polyimide,
Polyamideimide, polybenzimidazole, addition type polyimide, etc. have also come into use. Some of those thermosetting heat-resistant adhesives
There are some products that have excellent heat resistance, with no loss of adhesive strength even when exposed to temperatures of 260°C for long periods of time. On the other hand, ethylene-vinyl acetate copolymer,
Adhesives whose main components are thermoplastic resins such as polyamide resin, thermoplastic polyester, polyphenylene sulfide (hereinafter referred to as PPS), polysulfone, and polyethersulfone have significantly greater adhesive strength at temperatures of 150°C or higher. There is a problem with heat resistance because it is a thermoplastic resin. Furthermore, even with the thermosetting heat-resistant adhesive, which has excellent heat resistance, high temperature and high pressure conditions (e.g. 320°C, 50Kg/cm ³ ) are required to obtain sufficient adhesive strength.
curing at elevated temperatures (150 to 350°C) for long periods of time (1 to 5 hours); dehydration and deamination reactions occur during curing, making the work environment and At present, there are problems such as the need to pay attention to process control such as bonding conditions and the tendency for adhesive performance to fluctuate. The present inventors used thermoplastic resin as a base material, and
As a result of extensive research aimed at developing a thermoplastic heat-resistant adhesive with a tensile strength exceeding 100 Kg/ ^cm2 in the temperature range of 200°C, we found that potassium titanate was added to thermoplastic resin as an adhesion-improving filler. A thermoplastic heat-resistant adhesive characterized by the addition of 3 to 30% (by weight, the same hereinafter) fibers achieves the above objectives, and also has the advantage of being easy to process and does not cause deamine reactions, etc. The present invention was completed based on the discovery that the conventional problems such as ease of setting and management of adhesion conditions and maintenance of a good working environment because of the lack of adhesive bonding conditions can be solved. The thermoplastic resin that can be used in the present invention is PPS (repeat unit:

[Formula]), polysulfone (repeat unit: ), polyethersulfone (repeat unit:

[Formula] and polyetheretherketone (hereinafter referred to as PEEK, repeating unit: ) The main component is a resin selected from among the following. Each of these resins can be used as a commercially available product and may be in any form such as powder or pellet form at the time of use. In addition, for the purpose of improving adhesiveness or adhesion processability, nylon-6, nylon-12, nylon-6,6, nylon-6,10, nylon-6, Polyamide resin, such as 12, formula: or A thermoplastic polyester resin having repeating units or a copolymer consisting of both of the above units, formula: A thermoplastic polycarbonate resin having repeating units may be mixed. Potassium titanate fibers are most suitable as the adhesion-improving filler used in the present invention. Even if fine powder granular fillers such as calcium carbonate and silica sand are used, the average fiber diameter is 3 to 13 μm, and the average fiber length is
Even when glass fibers, carbon fibers, etc. having a normal fiber size of 2,000 to 12,000 μm are used, no improvement in adhesion is observed. The potassium titanate fiber has the general formula: K ₂ O・n (TiO ₂ ) or K ₂ O・n (TiO ₂ )・1/2H ₂ O (in the formula, n represents an integer from 2 to 8). The indicated average fiber diameter is less than 1 μm, and the average fiber length is 5 to 100 μm.
m and has an average fiber length 1 average fiber diameter (hereinafter referred to as aspect ratio) of more than 10,
Specifically, for example, potassium tetratitanate fiber, 6
Single compositions such as potassium titanate fibers or potassium octitanate fibers or mixed compositions thereof may be used in the present invention. The average fiber diameter, average fiber length, and aspect ratio of the above-mentioned potassium titanate fibers are the respective average values of the results of examining at least 10 or more fibers per field in at least 5 fields of view using a scanning electron microscope. If the average fiber diameter, average fiber length, and aspect ratio of the potassium titanate fibers are outside the above ranges, for example, the average fiber diameter is larger than 1 μm and the average fiber length is less than 5 μm, that is, the aspect ratio is less than 10. In this case, the improvement in adhesion strength is small and undesirable. Furthermore, long fibers with an average fiber length exceeding 100 μm are difficult to produce industrially and lack practicality. The potassium titanate fiber used in the present invention is "TISMO" (manufactured by Otsuka Chemical Co., Ltd.)
Average fiber diameter 0.2-0.5μ, commercially available under the trademark
m, average fiber length 10~20μm, aspect ratio 20~
100 high strength single crystal whiskers can be used as is. Adhesive strength and heat resistance can be improved by blending 3 to 30% of such potassium titanate fibers to the thermoplastic resin. If the blending amount is less than 3%, the effect of improving adhesive strength and heat resistance will be small;
If it exceeds , the adhesive strength at high temperatures will improve, but the adhesive strength at room temperature will tend to decrease, and potassium titanate fibers are very bulky, so it is difficult to use polysulfone, polyethersulfone, and PEEK other than PPS, which have a low melt viscosity. It becomes difficult to blend. Potassium titanate fibers are effective when used untreated, but epoxysilanes, aminosilanes,
Adhesion or water resistance is further improved by using potassium titanate fibers whose surface has been treated with a silane coupling agent such as acrylic silane or a titanate coupling agent such as isopropyltrioctanoyl titanate. In the present invention, by using microscopic and high-strength potassium titanate fibers, an improvement in the reinforcing effect of the adhesive layer and an improvement in heat resistance (improvement in thermal creep characteristics) are achieved. Use plastic resin as the main component, potassium titanate fiber as adhesive improving filler at 3-30%
Even when blended, the adhesive strength at high temperatures exceeding 150°C is significantly reduced, making it unsuitable as a thermoplastic heat-resistant adhesive. The method for preparing the thermoplastic heat-resistant adhesive of the present invention is (1) adding potassium titanate fiber 3 to thermoplastic resin powder.
A method of making a powder adhesive by adding ~30% and mixing with a mixer (2) A method of processing the powder adhesive obtained in (1) above into a film adhesive using a heated roll or an extruder (3) Any method can be applied, such as dispersing or dissolving thermoplastic resin pellets or powder in an organic solvent, adding potassium titanate fibers and uniformly dispersing them to create a solvent-based adhesive. It is. Further, the adhesive of the present invention can be used for bonding by a hot roll method, a hot press method, a high frequency heating method, an ultrasonic welding method, etc., and has a wide range of applications. Further, heat-resistant materials such as metals, ceramics, heat-resistant resins, etc. are used as the adherend, and bonding of metal-metal, metal-ceramics, metal-heat-resistant resin, etc. is possible. The thermoplastic heat-resistant adhesive of the present invention is a conventional solder,
It can be applied in place of riveting, welding, etc., and has the following advantages: (1) There is no extreme heating, so there is no deterioration of the adherend; (2) Load transmission is dispersed, so stress is reduced. No concentration (3) A self-damping effect can be expected against vibrations (4) It has advantages such as being lighter, more compact, automated, and can improve mass production speed, so it is used in electrical/electronic parts, automobiles, aircraft, etc. It is highly practical in assembly and parts installation processes. The present invention will be described in more detail below based on Examples, but the present invention is not limited to these Examples. Examples 1 to 6 and Comparative Example 1 PPS powder (trade name Ryton P-4, manufactured by Hodogaya Chemical Industry Co., Ltd.) was used as the thermoplastic resin, and TEISMO, a surface-untreated potassium titanate fiber, was added to the resin powder. Six types of powder adhesives were prepared by blending 5%, 10%, 15%, 20%, 25% and 30% of Teismo-D, respectively, while for comparison, Teismo-D
We prepared a product consisting only of Ryton P-4, which does not contain any. FIG. 1 is a conceptual diagram showing an example of an adhesive test piece used to measure various adhesive strengths of the adhesive of the present invention. Examples of sizes and dimensions in Figure 1 are (l): 15mm, m: 6mm, (n): 22mm, (o): 15
mmφ and (p): 6 mmφ, m is the fitting part of the gripping jig when measuring the tensile adhesive force, and A is the adhesive surface. Stainless steel (SUS304) machined to the shape and dimensions shown in Fig. 1 was used as the adherend.
The adhesive surface A shown in the figure was sandblasted with #100 abrasive grains, then ultrasonically cleaned in trichlorethylene for 10 minutes and dried with hot air. After preheating by standing in a 340 DEG C. oven for 30 to 50 minutes, 0.9 g of the powdered adhesive or Ryton P-4 was uniformly spread on the adhesive surface A and melted. These adherends are butted together with adhesive surface A, and the adhesive part is heated at 340 to 380°C in a protective heater at approximately 16 kgf/.
Adhesion was completed by applying a pressure of cm ² for 3 minutes and then cooling, and various adhesive strengths were measured. The various bond strengths were measured using an Instron type tensile tester as the tensile strength in the axial direction of the bonded test pieces, that is, the tensile bond strength (tensile speed 10 mm/min), and each test was performed five times under the same conditions. The average value of the measurement results was calculated and evaluated. The heat-resistant adhesive strength is the tensile adhesive strength at each temperature after leaving the bonded test piece in a high-temperature bath at 150 ° C and 200 ° C for about 30 minutes,
Continuous heat-resistant adhesive strength is the tensile adhesive strength after being stored in a test tube heat aging tester set at 180°C for 7 days. The measurement results are shown in Table 1.

[Table] From Table 1, the adhesive of the present invention containing 5 to 30% potassium titanate fiber has a heat-resistant adhesive strength of 150-200°C and a continuous heat-resistant adhesive strength of 100%.
Kgf/ ^cm2 , and the room temperature adhesive strength is maximum when the amount of potassium titanate fiber is around 10%, while the heat resistant adhesive strength is also maximum when the amount of potassium titanate fiber is around 20%. It can be seen that if the amount is too small or too large, the effect of improving adhesiveness decreases. Examples 7 to 8 and Comparative Examples 2 to 5 Polyethersulfone (trade name: VICTREX) PES100P, I.
CI Co., Ltd.) is dissolved in methylene chloride, and 20% of Teismo-D101 (trade name, manufactured by Otsuka Chemical Industries, Ltd.), which is an aminosilane-treated product of Teismo-D, is blended. Polyether ether ketone (trade name: Victrex) is used as a thermoplastic resin.
PEEK38G (manufactured by ICI) was mixed with 20% Teismo D101 to form pellets, and the pellets were extruded and stretched into a 100 μm thick film to produce film adhesives.
For comparison, only Victrex PES100P,
Exclusive to Victorex PEEK38G, calcium carbonate powder (product name NS#100, Nitto Funka Kogyo Co., Ltd.
Co., Ltd., average particle size 1.5 μm) or glass fiber (product name Glasslon CS03MA497, Asahi Fiber Glass)
Co., Ltd., with an average fiber length of 3 mm) mixed at 20%. The same adherends used in Examples 1 to 6 were used as test pieces and treated in the same manner as in Examples 1 to 6, and then the above solvent-based adhesive, film adhesive, and the above 4 prepared for comparison were used. The seeds were bonded in the same manner as in Examples 1 to 6, and for Example 8 and Comparative Example 5 below, the measurement of heat-resistant adhesive strength at 250°C was added, and the continuous heat-resistant adhesive strength was changed to 180°C. Various adhesive strengths were measured in the same manner as in Examples 1 to 6, except that the measurements were performed at 200°C. The second measurement result
Shown in the table.

[Table] From Table 2, it is seen that those using fine powder granular filler kaum carbonate powder or glass fiber instead of potassium titanate fiber have the same adhesion strength as those that do not contain anything, or have significantly higher adhesion. It can be seen that, while the adhesive strength of the present invention decreases, not only room temperature adhesive strength but also heat-resistant adhesive strength and continuous heat-resistant adhesive strength are significantly improved. Furthermore, when PEEK is used, the adhesive strength is good even at 250°C. Comparative Example 6 The same adherends as in Examples 1 to 6 were used, 100 parts by weight of Araldite GY252 (manufactured by Ciba Geigy) as the epoxy resin, and hardener as the hardening agent.
14 parts by weight of HY951 (manufactured by Ciba Geigy), 10 parts by weight of DY021 (manufactured by Ciba Geigy) as a diluent,
A thermosetting adhesive composition was prepared by mixing 20 parts by weight of Teismo D as potassium titanate fiber. After this adhesive was applied to the adherend, it was necessary to cure it at 60° C. for 4 hours under a pressure of 5 kg/cm ² , and it took a very long time to reach practical adhesive strength. On the other hand, the adhesives of Examples 1 to 6 may be left in an atmosphere of 340 to 380° C. under a pressure of about 16 kgf/cm ² for 3 minutes. In addition, the room temperature adhesive strength was 420Kg/ ^cm2 , which is the same as or even higher than the example, but the heat-resistant adhesive strength at 200℃ for 30 minutes was 89Kg/ ^cm2 , which is the standard for practicality.
It was less than 100Kg/cm ² , and the continuous heat-resistant adhesive strength at 180°C for 7 days was significantly lower to 94Kg/cm ² .

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing an example of an adhesive test piece used to measure various adhesive strengths of the adhesive of the present invention. (Main symbols in the drawing), m: inset part, A: adhesive surface.

Claims (1)

[Claims] 1 Adding 3 to 30% by weight of potassium titanate fiber as an adhesion-improving filler to a thermoplastic resin whose main component is a resin selected from polyphenylene sulfide, polysulfone, polyether sulfone, and polyether ether ketone. A thermoplastic heat-resistant adhesive characterized by: