JPS5968383A - Hot-melt adhesive composition - Google Patents

Abstract

PURPOSE:To provide a hot-melt adhesive composition containing a specified potassium titanate fiber and having a high adhesive strength. CONSTITUTION:The adhesive composition is prepared by adding 3-30wt% potassium titanate fiber having an average diameter of 1mu or smaller and an average length of 5-100mu, with the ratio of average length to average diameter exceeding 10, and treated with 0.5-5wt% silane coupling agent (e.g. gamma-glycidoxypropyl-trimethoxysilane), to a hot-melt resin composition consisting of a base polymer (e.g. ethylene/vinyl acetate copolymer), a tackifier resin (e.g. terpene resin), a wax (e.g. paraffin wax), an antioxidant [e.g. 2,6-di(tert-butyl)-p-cresol], a plasticizer, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hot melt adhesive composition with excellent adhesive strength. More specifically, by blending potassium titanate fibers into a hot melt resin composition,
The present invention relates to a hot melt adhesive composition with improved adhesive strength.

Compared to other adhesives and coatings, hot melt adhesive compositions have the following advantages: 1) DM products can be applied over a wide range; 2) No water or solvent is used, so there is no need for drying or cleaning processes.
It has unique features such as extremely fast adhesion, no toxicity or fire hazard as no solvent is used, and 100% active ingredients, which are economical as only a small amount of application is required. has.

Hot-melt products are manufactured by melt-mixing pace polymers, tackifying resins, waxes, plasticizers, fillers, anti-oxidation shavings, etc., depending on the application and the required performance.

Broadly dividing hot melt products based on their usage, they can be divided into five types: ■Hot melt adhesives, ■Hot melt coating agents, ■Hot melt sensitized adhesives, ■Hot melt paints, and ■Hot melt printing inks, but the majority of them are hot melt products. Mainly dominated by melt adhesives.

The ingredients that greatly affect the physical properties of hot melt products are:
Although it is known that the type of base polymer used in the hot melt adhesive composition depends on the type of base polymer used, the present inventors have improved the adhesive strength of the hot melt adhesive composition by blending specific potassium titanate fibers with a specific acid as a filler. We have discovered that this can be significantly improved, and have arrived at the present invention.

Conventionally, fillers used in hot melt adhesive compositions include calcium carbonate, barium sulfate, clay, talc,
Powdered materials such as magnesium oxide, magnesium carbonate, and titanium oxide, as well as fibrous materials such as asbestos, are used to (1) reduce the cost of the compound, and (2) reduce the shrinkage rate during hardening of hot melt products. (3) prevent excessive penetration into porous adherends; (4) improve blocking resistance of the formulation; (5) increase the heat capacity of the formulation. In order to increase the size, the open time becomes longer and wetting to the adherend material is improved (6)
It has the role of improving the heat resistance of the compound, but when these conventional fillers are blended, the adhesive strength remains almost the same or decreases when a large amount is blended. It was taken for granted.

However, when the average fiber diameter is 1 μ or less and the average fiber length is 5 to 1
When potassium titanate fibers with a diameter of 00μ and an average fiber length/average fiber diameter of 10 or more are blended in an amount of 6 to 60%, the adhesive strength can be doubled depending on the adherend. They have discovered that by processing, it is possible to improve the performance by a factor of six.

The potassium titanate fiber used in the present invention has the general formula "20·n (T i Oz ) or 20-n
(Tie,) - Single crystal fiber represented by -zH20 (wherein n represents an integer of 2 to 8), specifically, for example, potassium titanate fiber, potassium hexatitanate fiber, or potassium octatitanate fiber. It may be a single composition of fibers or a mixed composition thereof, with an average fiber diameter of 1 μ or less, an average fiber length of 5 to 100 μ, and an average fiber length/average fiber diameter (aspect ratio) of 10 or more. It is.

Here, the average fiber diameter, average fiber length, and aspect ratio of the potassium titanate fibers were measured using a scanning electron microscope with at least 5 fields of view and at least 10 fibers per field of view. The aspect ratio refers to the average value obtained by dividing the fiber length of the fiber by the fiber diameter.

When 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 μ and the average fiber length is smaller than 5 μ, that is, the aspect ratio is smaller than 5. This is not preferable because the effect of improving adhesive strength is small. Further, fibers having an average fiber length of more than 100 μm are difficult to produce industrially and lack practicality.

The potassium titanate fibers used in the present invention can be used as they are, commercially available under the trade name Teismo J (manufactured by Otsuka Chemical Co., Ltd.), which has an average fiber diameter of 0.2 to 0.5μ. , a high-strength single crystal whisker with an average fiber length of 10-20μ and an aspect ratio of 20-100.

By blending the potassium titanate fibers into the hot melt adhesive composition in an amount of 6 to 60% by weight, the adhesive strength can be greatly improved; however, if the blending amount is less than 6% by weight, the improvement effect is poor; If it exceeds M% by weight, the price of the potassium titanate fibers is relatively high, and the effect of improving adhesion is small in proportion to the amount of the potassium titanate fibers added, resulting in a decrease in practicality.

The potassium titanate fibers are effective even when used untreated, but they can be used with ordinary coupling agents such as silane coupling agents such as vinyl silane, epoxy silane, amino silane, acrylic silane, or titanate coupling agents. Surface treatment with an agent further improves adhesive strength. Among them, r-glycidoxypropyltrimethoxysilane, β-(6,4-epoxycyclohexyl)
It is highly effective to use potassium titanate fibers treated with a coupling agent by adding about 0.5 to 5% by weight of an epoxy-based silane coupling agent such as ethyltrimethoxysilane.0 Can be used in the present invention The hot melt adhesive resin composition can be applied to all products currently in use. That is, as a base polymer, ethylene vinyl acetate copolymer (vinyl acetate content 10 to 50%, M engineering 1 to 100%) is used.
0), polyamide, polyester, polyethylene,
Synthetic rubber, ethylene ethyl acrylate, atactic polypropylene, polyvinyl acetate, EVA acrylic terpolymer, etc. can be used, but most commercially available products are ethylene vinyl acetate copolymers.

As the tackifying resin, rosin and its derivatives, terpene resin, petroleum resin, etc. are used. Wax is added to reduce the melt viscosity of the compound and improve workability, but it is rarely used when adhesive strength is important.

As the wax, paraffin wax, microcrystalline wax, low molecular weight polyethylene wax, carnauba wax, etc. can be used. The antioxidant is 2,6-di(tert-butyl)-p- to improve thermal stability.
Cresol, tri(nonylphenyl) phosphite, etc. are often added alone or in combination in an amount of 0.1 to 1% by weight.

In addition, depending on the application, fillers other than the potassium titanate fibers, such as plasticizers, special oligomers, asphalt, and the above-mentioned calcium carbonate, may also be mixed and used.

Therefore, the hot melt adhesive composition of the present invention can be prepared by a conventionally known method, that is, a base polymer, a tackifying resin, a wax, a plasticizer, a filler (including potassium titanate fiber), etc.
, antioxidant, etc. are melted and mixed in a melting device such as a heating tank, and then provided in shapes such as blocks, biscuits, strips, belts, ropes, and films.

In addition, in order to use all of these, it is necessary to melt the composition (120 to 200°C) in a heated melt coating device (applicator) and apply it to the adherend as a liquid, or to use the composition in the form of a film or powder. Adhesion methods such as high-frequency heating, ultrasonic welding, and hot pressing have also been used.

The hot melt adhesive composition of the present invention has higher adhesive strength than conventional products, and is particularly suitable for hot melt adhesives for partial assembly, woodworking, and traffic paint for white lines and yellow lines painted on roads. It can be applied to a very wide range of areas such as hot melt coating R1, transportation vehicles, electrical elements, metals, machinery, daily necessities, architecture, woodworking, and civil engineering.

Next, the present invention will be explained in more detail with reference to Examples.
These examples are merely practical examples, and the present invention is not limited to these examples in any way.

Examples 1 to 6 Fi'VA hot melt adhesive (ethylene vinyl acetate copolymer, 28% for vinyl acetate tables, M work 150, softening point 90°0) and potassium titanate fibers of a specified style were mechanically bonded. Blend and place between 100°C hot plates, 2
It was pressed for 2 to 6 minutes at a pressure of 0 kg f/cm 2 and then cooled in air to obtain a film-like hot melt adhesive having a thickness of 0.15 to 0.2 mm.

A commercially available phenolic resin rod with a diameter of 5 mm was used as the adherend, and an ultrasonic welder (frequency m 15 k) as shown in the drawing was used.
Hz, output L2kw, maximum amplitude 40μm), -H
part (horn side) 20mm, lower part (cradle side) 4Qmm
The adhesive surface was finished with #100 emery paper, and the pressure applied to the adhesive surface was 40kpf/cm.
, After C welding for 6 seconds with a vibration time of 6 seconds, [) (J note 1 was maintained for 6 seconds to complete the bonding, and an axial tensile test was performed to determine the tensile bond strength, which was 19 N. force J′
The results are summarized in Table 1.

When potassium titanate fibers treated with epoxy silane are added at 15% by weight, the tensile adhesion strength is improved by nearly 6 times as compared to F without the addition, and practical performance can be obtained. Calcium carbonate and asbestos have no effect on improving adhesion.

Table 1 Note (1) Surface pretreatment j4 ■ Potassium titanate fiber (Otsuka f
(3) Average particle size 1.577 (NS#100,
(manufactured by Nitto Funkako In) (4) Nozawa wet asbestos tailing In the ultrasonic welding machine shown in the drawing, (1) is the oscillator, (2) is the converter, (8) Lt horn, and (4) is the adhesion (5) is a blast rubber, (6) is a film-like hot melt adhesive, (7) is a tearable material holder, (8) is a pedestal, and (9) is an air cylinder.

Examples 4 to 8 A hot-melt adhesive assembly (mixing composition of two materials and traction r'A adhesive The strength was determined.The results are shown in Table 2.Although the adhesion strength to J0 polyacetal resin is originally high, in this case too, potassium ditanate \culm:string, 1, +1 treated with epoxy silane was used for S~60wt. 9-chi compound (4-thickness adhesive strength 1g
Among them, the 10% I% culmness seems to be suitable for eel.

Table 2 Examples 9 to 12 As adhesion, 20 mm on the upper part (horn fl!II)
Long copper phase (S 45CI), 41) at the bottom (cradle side)
The relationship between the composition of the hot melt adhesive composition and the tensile adhesive strength was determined in the same manner as in Example 1, except that a polyacetal resin with a diameter of mm was used. The results are shown in Table 6.

These results show that BHy, which has conventionally not been able to achieve practical adhesive strength, is used to bond engineering plastics and metals.
It has been found that when approximately 10% by weight of potassium titanate fibers, especially those treated with epoxy silane, are blended into the AP hot melt adhesive, practical adhesive strength can be obtained and the adhesive will be effective in assembling mechanical parts.

Table 6

[Brief explanation of drawings]

The drawing is a schematic side view of an ultrasonic welding device used for bonding adherends in a practical example of the present invention. (Drawing code) (J): Oscillator (2): Converter (3): Horn (4): Adhesive + A (5) 2-buffer rubber (6): Hot melt adhesive (7);゛1 Holder (8); pedestal (9): Air cylinder patent applicant Otsuka Chemical Products Co., Ltd.

Claims (1)

[Scope of Claims] 1. A hot powder characterized by containing 6 to 60% by weight of potassium titanate fibers having an average fiber diameter of 111 or less, an average fiber length of 5 to 100μ, and a ratio of average fiber length/average fiber diameter of 10 or more. Melt adhesive composition. 2. The hot melt adhesive composition according to claim 1, wherein the potassium titanate fibers are treated with an epoxy-based silane coupling agent. 6. The hot melt adhesive composition according to claim 1 or 2, which is characterized in that extremely excellent adhesive performance can be obtained by ultrasonic welding.