JPH04320477A - Hot melt adhesive - Google Patents

Abstract

PURPOSE:To obtain the title adhesive which can be molten within a short heating time by mixing two hot melt resins having different melting points. CONSTITUTION:The title adhesive is obtained by mixing a (particulate) hot melt resin (A) selected from among an ethylene/vinyl acetate copolymer resin, PE, ethylene/ethylacrylate copolymer resin, a polyamide, etc., with another (particulate) hot melt resin (B) having a melting point lower than that of component A and selected from among resins similar to component A, etc.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to hot melt adhesives, and more particularly to improvements in adhesives for hot melt bonding.

0002

BACKGROUND OF THE INVENTION Hot melt adhesives are usually based on thermoplastic resins. The melting point of a hot melt adhesive is determined by the characteristics of the resin used. (a) When heated above that temperature, the solid resin softens and melts, develops adhesive strength, and adheres to the adherend. (b) By cooling, the resin softens again, develops cohesive force, and provides the necessary adhesive strength. The reactions (a) and (b) above are reversible, and the softening and melting temperatures govern the heat resistance of the adhesive. Furthermore, when hot melt bonding is actually performed, the temperature is generally set slightly higher (+20 to 30° C.) than the above temperature.

0003

[Problems to be Solved by the Invention] To perform hot melt bonding in a short time, heating at a temperature higher than the required heat resistance is required for the above reasons, which may damage the adherend or damage the adherend. It was necessary to select a heat-resistant treatment or heat-resistant material that can withstand high temperatures, or to take measures such as cooling the adherend. As a result, more heat-resistant methods than necessary have been forced to increase costs.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hot melt adhesive that can be heated and melted in a shorter time than conventional adhesives.

Another object of the present invention is to provide a hot melt adhesive that is easy to manufacture.

[0006]

[Means for Solving the Problems] In order to achieve the above-mentioned problems, the present invention provides a hot melt resin (hereinafter simply referred to as A resin) with a hot melt resin (hereinafter simply referred to as A resin) having a lower melting point than the hot melt resin. , simply referred to as B resin).

The present invention is also characterized in that the powder of resin A is mixed with the powder of resin B, which has a lower melting point than resin A.

[0008] Resins A and B are appropriately selected from those having different melting points from ordinary hot melt resins such as ethylene/vinyl acetate copolymer resin, polyethylene, ethylene/ethyl acrylate copolymer resin, polyamide, etc. be able to. The larger the mixing ratio of the B resin, the faster it will melt.

[0009]

[Operation] Upon heating, the low melting point B resin first melts and stores heat. On the other hand, resin A is melted by both the amount of heat generated by heating and the conductive heat obtained by contact with the melted resin B. Therefore, A resin melts faster than A resin alone.

Next, one embodiment of the present invention will be described with reference to FIGS. 1 to 5. First, resin A and resin B shown in Table 1 were prepared.

[0011]

[Table 1]

[0012] As resin A, "Meltron A-704" (trade name of hot melt resin for hot melt adhesives) manufactured by Diapolymer Co., Ltd. is used, and as resin B, "Meltron MP-1010" manufactured by Diapolymer Co., Ltd. is used. ” (trade name of hot melt resin for hot melt adhesive) was used.

Next, resin A and resin B were mixed at the mixing ratio (weight ratio) shown in Table 2, and sample No. 1~
No. 4 hot melt adhesive was made.

[0014]

[Table 2]

[0015] Furthermore, sample No. 1 and sample N
O. 4 is a comparison. Sample No. 2 and sample sample no. The powder of No. 3 is A as shown in Figure 2.
Resin 1 and B resin 2 are in a mixed state.

[0016] However, the sample No. 1~NO
．． Each powder of No. 4 was spread on a horizontal substrate, and the melting time of each powder was examined. Sample No. 1~NO. The melting times of No. 4 were as shown in graphs I, II, and III in FIG. That is, graph I is sample No. 1~NO
．． Graph II shows the melting time when Sample No. 4 is placed in an atmosphere at 190°C. 1~NO. 4 to 1
It shows the melting time when placed in an atmosphere of 80°C. In graphs I and II, the larger the amount of B resin mixed,
It is observed that the melting time of the powder is short. As shown in graph II, the powder melting time of resin A alone (sample no. 4) was 19 minutes, but when the mixing ratio of resin A and resin B was 50% and 50% (sample no. ．．
The melting time of powder 2) is 13 minutes, and it is observed that the melting time of the latter is reduced by 6 minutes. In addition, graph II
I is sample No. 1~NO. This is a case where sample No. 4 is placed in an atmosphere at 160°C. 2~N
O. No. 4 did not melt.

When resin B is mixed with resin A, the time required for melting gradually decreases as the mixing ratio of resin B increases. The reason for this is thought to be as follows. That is, when the powder of A resin 1 and the powder of B resin 2 shown in FIG. 2 are heated, as shown in FIG.
is completely melted, becomes molten particles 2A, and begins to accumulate heat. On the other hand, as shown in FIG. 4, resin A 1 becomes molten particles 1A as shown in FIG. 5 due to both the amount of heat generated by heating and the conductive heat obtained from contact with melted resin B 2 (molten particles 2A). , and both molten particles 1A and 2A are connected melt 3
becomes. Therefore, A resin 1 melts in a shorter time than when A resin alone is used.

Note that after bonding, resin A and resin B are in a mixed state, but they do not melt until the melting point of resin A is reached.

[0019] However, the sample No. The melted powder of No. 2 was applied onto a resin plate, and the cloth bodies were overlapped and hot-melt bonded. For adhesion, a synthetic resin plate was placed on a horizontal substrate, and sample No. After uniformly applying the melted product No. 2, the fabrics were stacked on top of each other, and a press plate at 200° C. was pressed onto the fabrics for 1 second. The adhesive state of the fabric was good, and no thermal discoloration occurred on the surface of the fabric.

[0020]

Effects of the Invention Since the present invention has a composition in which resin A is mixed with resin B having a low melting point, the hot melt adhesive can be heated and melted at a low temperature and in a short time. Therefore,
The hot-melt bonding process can be completed in a short time, increasing the efficiency of the bonding process, and also eliminating inconveniences caused by the heat of the adherend during bonding, such as thermal discoloration. Further, in the present invention, when the hot melt resin and the low melting point thermoplastic resin are made into powder, mixing of both resins is simple and manufacturing is easy.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between resin mixing ratio and melting time.

FIG. 2 is a schematic diagram showing a mixed state of resin A and resin B.

FIG. 3 is a schematic diagram showing the molten state of resin B.

FIG. 4 is a schematic diagram showing the state of contact between resin A and melted resin B.

FIG. 5 is a schematic diagram showing the melted state of both resins.

[Explanation of symbols]

1 A resin 1A, 2A Melted particles 2 B resin 3 Melt

Claims (2)

[Claims] 1. A hot melt adhesive comprising a hot melt resin mixed with a hot melt resin having a lower melting point than the hot melt resin. 2. A hot melt adhesive characterized in that the hot melt resin powder is mixed with a hot melt resin powder having a lower melting point than the hot melt resin.