JP2001172590A - Hot melt adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot melt adhesive which has well-balanced properties and which has at least one improved property selected from high heat resistance, low temperature at which coating is possible, low viscosity at coating and high adhesion. SOLUTION: The hot melt adhesive comprises (A) an ethylene/vinyl acetate copolymer with a vinyl acetate content of 10 wt.% or more and 25 wt.% or less, (B) a tackifying resin and (C) a wax with a softening point of 100 deg.C or more and has a viscosity at 180 deg.C of 10-100 Pa.s. More specifically, the hot melt adhesive comprises 150-200 pts.wt. of (B) the tackifying resin based on the total (100 pts.wt.) of (A) the ethylene/vinyl acetate copolymer with a vinyl acetate content of 10 wt.% or more and 25 wt.% or less and (C) the wax with a softening point of 100 deg.C or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-melt adhesive, and more particularly to an electronic component having lead wires, such as a resistor element and a capacitor element, arranged and held in a slender shape using the lead wires. Hot-melt adhesive used for an adhesive tape.

[0002]

2. Description of the Related Art A certain type of adhesive tape has been used to hold electronic components having lead wires (usually two), such as a resistor element and a capacitor element, in a staggered manner using the lead wires. Used in the manufacturing process of circuit boards and the like in the electronics industry. Hereinafter, in this specification, "electronic component" refers to a resistor element, a capacitor element, and the like,
It refers to one with two (usually two) lead wires. Further, in this specification, a certain type of adhesive tape for holding an electronic component by sandwiching the lead wire of the electronic component described above is referred to as an “electronic component holding tape”, and the “adhesive tape” includes: In addition to the electronic component holding tape, a tape generally used as a so-called adhesive tape is also included. For example, a tape used as a cushioning material having urethane foam or the like as a base material is also included. In the present specification, the "substrate" of the adhesive tape is a substrate for producing the adhesive tape,
These may be in the form of a sheet or a film, for example,
Examples of the base material include paper, plastic, metal foil, and a laminate thereof, and an adhesive tape for fixing electronic components such as a capacitor element (electronic component holding tape).
As a base material, for example, crepe paper can be preferably used.

[0003] Lead wires attached to these electronic components are:
By being sandwiched between the electronic component holding tape and a normal (non-adhesive) tape or between two electronic component holding tapes, the electronic component is slid in the longitudinal direction and the vertical direction of the electronic component holding tape. It is arranged and held in a shape, so that an array of electronic components is manufactured. In the manufacturing process of a circuit board or the like, the electronic component is released from the arrangement by being cut off the lead wire between the electronic components arranged in a streak and the electronic component holding tape, and incorporated into the circuit board or the like. It is. The production of a series of circuit boards and the like from the production of the above-described arrangement of electronic components to the incorporation of the electronic components into the circuit boards and the like is usually performed by an automatic system. Therefore,
The accuracy of the arrangement of the electronic components described above, such as the spacing of the electronic components and the perpendicularity of the electronic components to the electronic component holding tape, includes:
Extremely high precision is required.

As an adhesive used for such an electronic component holding tape, a solvent-based adhesive is known. However, solvent-based adhesives have problems such as protection of the global environment, regulations on organic solvents, and simplification of the adhesive tape manufacturing process. Became.

As an adhesive for solving such a problem,
The present inventors have focused on hot melt adhesives. By the way, Japanese Patent Application Laid-Open No. 10-60394 discloses a solvent-based adhesive, but there is a description about a hot melt adhesive in a part thereof. This hot melt adhesive is prepared by adding 50 parts of a rosin resin having a softening point of 130 ° C. to 100 parts of an ethylene-vinyl acetate copolymer having a vinyl acetate content of 19% by weight.
(Japanese Unexamined Patent Publication (Kokai) No. 10-6039).
No. 4 Publication Example 5). With regard to the performance of the adhesive tape using this hot melt adhesive, only the rate of decrease in adhesive strength due to humidification storage is disclosed.

[0006] In addition to a small decrease in the adhesive strength due to humid storage, other properties are required for the hot melt adhesive. First, it is required that the electronic component held by the electronic component holding tape does not peel off or shift from the tape base at about 60 to 70 ° C., that is, high heat resistance is required. In this specification, "heat resistance" means that the arrangement state of the electronic components held on the tape does not substantially change with the temperature of the surrounding environment. Therefore, “high heat resistance” means that the temperature at which the arrangement state of the electronic components substantially changes is high, and more specifically, the arrangement state of the electronic components is substantially 60 to 70 ° C. Does not change. Next, the hot melt adhesive is also required to have a low viscosity at the time of application. This is because the lower the viscosity at the time of coating, the more easily and evenly the hot melt adhesive can be applied to the base of the electronic component holding tape. Because it is advantageous.

[0007] Then, the present inventor examined other properties of this hot melt adhesive and found that those other properties were insufficient. That is, it has been found that in this hot melt adhesive, the viscosity increases as the heat resistance increases, and the heat resistance decreases as the viscosity decreases. Therefore, if the heat resistance is sufficient, the viscosity at the time of application becomes high, and it becomes difficult to uniformly apply the hot melt adhesive to the base material of the electronic component holding tape. Therefore, even with the use of the hot melt adhesive disclosed in Japanese Patent Application Laid-Open No. 10-60394, it is difficult to manufacture an electronic component holding tape for obtaining an array of electronic components with extremely high alignment accuracy. Conceivable.

[0008]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and the problem is that the heat resistance is higher than that of a conventional hot melt adhesive.
Low coating temperature, low coating viscosity,
It is an object of the present invention to provide a hot-melt adhesive having a good balance between improved properties and improved at least one property. Further, it is an object of the present invention to provide an electronic component holding tape in which at least one of high heat resistance, high adhesive strength, and high accuracy of arrangement of electronic components is improved. .

[0009]

According to one aspect of the present invention, there is provided a new hot melt adhesive which comprises:
(A) an ethylene-vinyl acetate copolymer having a vinyl acetate content of 10% by weight or more and 25% by weight or less, (B) a tackifying resin, and (C) a wax having a softening point of 100 ° C or more, A hot melt adhesive having a viscosity at 180 ° C. of 10 to 100 Pa · s, which is particularly suitable as a hot melt adhesive used for an electronic component holding tape.

[0010]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, "(A) an ethylene-vinyl acetate copolymer having a vinyl acetate content of 10% by weight or more and 25% by weight or less" is a so-called copolymer of ethylene and vinyl acetate. An ethylene-vinyl acetate copolymer, which may be a single type of ethylene-vinyl acetate copolymer alone (hereinafter also referred to as “single”) or a combination of a plurality of types of ethylene-vinyl acetate copolymer (hereinafter, “combination”) ) May be used, and if the vinyl acetate content alone or in combination is 10% by weight or more and 25% by weight or less,
There is no restriction.

[0011] In this specification, the term "vinyl acetate content" refers to the weight% (or mass%) measured by a method similar to the method described in JIS K6730. In the present specification, “(A) an ethylene-vinyl acetate copolymer having a vinyl acetate content of 10% by weight or more and 25% by weight or less” is also referred to as “(A) an ethylene-vinyl acetate copolymer”. . (A) The ethylene-vinyl acetate copolymer has a function of improving the adhesive strength and holding power of the hot melt adhesive. Incidentally, when the vinyl acetate content of the (A) ethylene-vinyl acetate copolymer is less than 10% by weight,
(A) The problem that the adhesion between the ethylene-vinyl acetate copolymer and the base material is reduced may be caused, and if it exceeds 25% by weight, the problem that the heat resistance is reduced may be caused.

In the present invention, when “(A) ethylene-vinyl acetate copolymer” is used alone (consisting of one kind), “vinyl acetate content” is a single value of the ethylene-vinyl acetate copolymer. In the case where “(A) ethylene-vinyl acetate copolymer” is a combination (consisting of a plurality of types), “vinyl acetate content” is a value of the vinyl acetate content of the combination. In any case, the vinyl acetate content of the “(A) ethylene-vinyl acetate copolymer” is more preferably from 10% by weight to 25% by weight, and particularly preferably from 15% by weight to 23% by weight.

Therefore, when "(A) ethylene-vinyl acetate copolymer" is a combination, the vinyl acetate content of each of the ethylene-vinyl acetate copolymers to be combined is not necessarily 10% by weight or more and 25% by weight or less. No need to be. It is sufficient that the vinyl acetate content as a whole of the combination obtained by the combination is 10% by weight or more and 25% by weight or less. In this case, the vinyl acetate content of each of the ethylene-vinyl acetate copolymers to be combined is preferably 10% by weight or more and 25% by weight or less, and more preferably 15% by weight or more and 23% by weight or less. Particularly preferred.

Incidentally, as the vinyl acetate content of the combination,
A value calculated using the formula (I) may be used. Vinyl acetate content (% by weight) of the combination = (a1 × a2 + b1 × b2 + c1 × c2...) / 100 (I) [However, in the formula (I), a1, b1, c1,.
Is the ethylene-vinyl acetate copolymer (A, B,
C,...), A2, b2, c
2,... Are the respective vinyl acetate contents of the combined ethylene-vinyl acetate copolymers (A, B, C,...). ]

(A) The melt index (or melt flow rate) of the ethylene-vinyl acetate copolymer is not particularly limited as long as the hot melt adhesive of the present invention exhibits its performance. 1 to 1000 is preferable, and 0.5 to 800 is more preferable. (A) ethylene-
When the melt index of the vinyl acetate copolymer is less than 0.1, the viscosity becomes high, which may cause a problem that the wettability to the substrate is reduced. Can occur.

Here, when the “(A) ethylene-vinyl acetate copolymer” is used alone, the “melt index” is
It is a single value of the ethylene-vinyl acetate copolymer,
When "(A) ethylene-vinyl acetate copolymer" is a combination, the "melt index" is the value of the melt index of the entire combination.

Therefore, when “(A) ethylene-vinyl acetate copolymer” is a combination, the melt index of each of the ethylene-vinyl acetate copolymers to be combined is:
There is no particular limitation, and the melt index as a whole of the combination obtained by the combination is preferably 0.1 to 1000, and is preferably 0.5 to 80.
0 is more preferable. In this case, each of the melt indexes of the ethylene-vinyl acetate copolymer to be combined is preferably from 0.1 to 1,000,
More preferably, it is 0.5 to 800.

Such an ethylene-vinyl acetate copolymer (A) can be produced by a known method, but a commercially available product can be used. For example, (A) ethylene-
Sumitate HA-20 (20VA20MI) (trade name) and Sumitate HE-10 (20VA300MI) (trade name) manufactured by Sumitomo Chemical Co., Ltd., and EVA manufactured by Mitsui-DuPont Polychemical Co., Ltd. as vinyl acetate copolymers. Flex 640 (10VA75MI) (trade name), Evaflex 460 (19VA2.5MI) (trade name), Evaflex 450 (19VA15MI) (trade name), and Tosoh Ultrasen 626 (15V)
A14MI) (trade name) and Ultracene 680 (20
VA160MI) (product name) and the like. In the present specification, “○ VA” means that the vinyl acetate content is
% By weight, and “XXMI” means that the melt index is XX. These (A) ethylene-vinyl acetate copolymers can be used alone or in combination of two or more as described above.

In the present invention, "(B) tackifying resin"
Is not particularly limited as long as it is a so-called tackifying resin usually used for a hot melt adhesive.
(B) A tackifying resin is a function of improving the wettability of a hot melt adhesive, imparting an initial adhesive strength, and lowering the melt viscosity of the hot melt adhesive to improve workability in a coating process. Having. As the “(B) tackifying resin”, for example, aromatic petroleum resin, aliphatic petroleum resin, aliphatic-aromatic petroleum resin, terpene resin, rosin resin, modified terpene resin, modified rosin resin And at least one selected from styrene-based petroleum resins and the like.

Further, in the present invention, it is preferable to use "hydrogenated tackifying resin (hereinafter referred to as" hydrogenated tackifying resin ")" as "(B) tackifying resin". The hydrogenated tackifier resin is a tackifier resin obtained by partially or completely hydrogenating the above-mentioned (B) tackifier resin, and is colorless or nearly white, and has carbon-
By reducing the number of double bonds between carbons, the odor is reduced and substantially no odor is felt, and the oxidative deterioration during melting or long-term use is reduced. As "hydrogenated tackifying resin", for example, partially or completely hydrogenated, aromatic petroleum resin,
Examples include at least one selected from aliphatic petroleum resins, aliphatic-aromatic petroleum resins, terpene resins, rosin resins, modified terpene resins, modified rosin resins, and styrene petroleum resins. it can.

The softening point of the tackifying resin (B) is not particularly limited as long as the hot melt adhesive of the present invention exhibits its performance, but is preferably from 60 to 185 ° C.
100-160 ° C is particularly preferred. (B) If the softening point of the tackifier resin is lower than 60 ° C., a problem of a decrease in heat resistance may occur. If the softening point exceeds 185 ° C., it is difficult to melt and mix the adhesive. Can occur.

The tackifier resin (B) can be produced by a known method, but a commercially available resin can be used.
For example, as the (B) tackifying resin, Clearon K-100 (trade name), Clearon M-105 (trade name), and YS Resin TO-1 manufactured by Yashara Chemical Co., Ltd.
05 (trade name), Arakawa Chemical Co., Ltd. Super Ester T-125 (trade name) and KE-604 (trade name), and Arizona Chemical Co., Ltd. Niletz (Niret)
z) V2040HM (trade name) can be exemplified. These (B) tackifier resins can be used alone or in combination of two or more.

In the present invention, "(C) the softening point is 100
"Wax above ℃" is a so-called wax,
There is no particular limitation as long as the softening point is 100 ° C. or higher. (C) The wax having a softening point of 100 ° C. or higher has functions such as lowering the viscosity of the hot melt adhesive and improving wettability. Hereinafter, “(C) wax having a softening point of 100 ° C. or higher” is also referred to as “(C) wax”. (C) The softening point of the wax is particularly preferably from 110 to 140C. (C) If the softening point of the wax is lower than 100 ° C., there is a problem that the heat resistance is reduced.

As the wax (C), for example, polyolefin waxes such as polyethylene wax and polypropylene wax, each of which has a softening point of 100 ° C. or more, synthetic wax produced by Fischer-Tropsch method, polymerization method or decomposition method , Microcrystalline wax, and a copolymer of ethylene and at least one selected from vinyl acetate, acrylic acid, methacrylic acid, acrylate, and methacrylate and having a number average molecular weight of 4,000 or less Etc. can be exemplified. (C) The wax can be produced by a known method, but a commercially available wax can be used. These (C) waxes can be used alone or in combination of two or more.

In the hot melt adhesive of the present invention,
(A) Weight ratio of ethylene-vinyl acetate copolymer to (C) wax ((A) ethylene-vinyl acetate copolymer:
(C) wax) is preferably from 9: 1 to 1: 1 and 7:
1-2: 1 is particularly preferred. In addition, the hot melt adhesive of the present invention is obtained by adding (B) to the total (100 parts by weight) of (A) an ethylene-vinyl acetate copolymer and (C) a wax.
It is preferable that the tackifier resin be contained in an amount of 150 to 200 parts by weight, particularly preferably 155 to 170 parts by weight.

In the hot melt adhesive of the present invention,
Various "additives" commonly used in hot melt adhesives can further be included. Where "additives"
Is to improve the properties of hot melt adhesives comprehensively,
To maintain the quality of the hot melt adhesive,
For example, stabilizers (antioxidants, etc.) for improving thermal stability, oxidation resistance, and weather resistance, ultraviolet absorbers for preventing deterioration due to ultraviolet rays, flame retardants, and blocking prevention of hot melt adhesives. At least one selected from an agent and an inorganic filler for suppressing shrinkage can be exemplified.

As such additives, commonly used additives can be used. As the antioxidant, for example, a phenol antioxidant, a phosphorus antioxidant, and a sulfur antioxidant are preferable. As the ultraviolet absorber, for example, benzophenone-based ultraviolet absorber,
Benzotriazole ultraviolet absorbers such as 2- (2-hydroxy-5-methylphenyl) benzotriazole are preferred. The above-mentioned additives can be used alone or in combination. The hot melt adhesive of the present invention preferably contains 0.1 to 5 parts by weight of an additive based on 100 parts by weight of the total of (A) to (C), and 0.2 to 5 parts by weight.
More preferably, it contains 4 parts by weight, particularly preferably 0.3 to 3 parts by weight. The hot melt adhesive of the present invention is obtained by mixing a desired amount of the above-mentioned components to obtain desired properties,
It can be obtained by melting by heating.

Further, the hot melt adhesive of the present invention has
The viscosity at 0 ° C. is 10 to 100 Pa · s. The viscosity at 180 ° C. of the hot melt adhesive is more preferably from 10 to 80 Pa · s, particularly preferably from 10 to 50 Pa · s. When the viscosity at 180 ° C. of the hot melt adhesive is less than 10 Pa · s, the cohesive force of the hot melt adhesive is significantly reduced at about 60 to 70 ° C., and the holding power of the hot melt adhesive is reduced. Caused the problem, 100P
If it exceeds a · s, it becomes difficult to uniformly apply the hot melt adhesive to the substrate by melt coating. The “viscosity at 180 ° C. of the hot melt adhesive” refers to a viscosity measured at 180 ° C. using a Brookfield viscometer (spindle 27).

The above-mentioned hot melt adhesive of the present invention is used in fields where hot melt adhesives are usually used, for example, in the field of bonding nonwoven fabric and / or paper, adhesive tapes, automobiles and houses. Although it can be used in tapes and laminations for cushioning materials, it is particularly suitable as a hot melt adhesive used for an electronic component holding tape for holding electronic components by sandwiching lead wires. In the present invention, a coating method usually used for a hot melt adhesive, for example, using a coating method such as a slot coating method, a melt blow method, a spiral method, and a foam method, usually using a hot melt adhesive Can be used in certain fields. In particular,
By applying the hot melt adhesive of the present invention to a base material of an adhesive tape, for example, paper, non-woven cloth, and a metal foil such as an aluminum foil, an electronic component holding tape and a cushioning material tape can be easily and easily obtained. Etc. can be manufactured.

Further, by producing an adhesive tape using the hot melt composition of the present invention, heat resistance and adhesive strength are higher as compared with the case where the adhesive tape is produced using a conventional hot melt adhesive. The present invention can provide an adhesive tape in which at least one of the properties and the uniformity of the coated surface of the base material is improved, and the property is improved.

In particular, when the electronic component holding tape is manufactured using the hot melt composition of the present invention, the heat resistance is higher and the adhesive strength is higher than when the tape is manufactured using a conventional hot melt adhesive. To provide an electronic component holding tape in which at least one characteristic is improved, that is, the electronic component holding tape is high in accuracy and the arrangement accuracy of the electronic component is high due to the high uniformity of the coated surface of the base material. Can be.
Furthermore, by using the above-mentioned electronic component holding tape, at least one property of higher heat resistance, higher adhesive strength, and higher alignment accuracy than using the conventional electronic component holding tape is described. Can provide an improved arrangement of electronic components.

[0032]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, these examples are only one embodiment of the present invention, and the present invention is not limited by these examples. is not.

The materials (A) to (D) used for preparing the hot melt adhesives of Examples and Comparative Examples are shown below. (A
1) to (A4) are (A) vinyl acetate content of 10% by weight.
This is an ethylene-vinyl acetate copolymer having a content of not less than 25% by weight: (A1) having a vinyl acetate content of 20% by weight.
And an ethylene-vinyl acetate copolymer having a melt index of 20 (Sumitate HA- manufactured by Sumitomo Chemical Co., Ltd.)
20 (20VA20MI) (trade name));
2) is an ethylene-vinyl acetate copolymer having a vinyl acetate content of 20% by weight and a melt index of 300 (Sumitate HE-10 (20V, manufactured by Sumitomo Chemical Co., Ltd.)
(A300MI) (trade name)); (A3) has a vinyl acetate content of 10% by weight and a melt index of 75.
Ethylene-vinyl acetate copolymer (Evaflex 640 (10VA manufactured by DuPont-Mitsui Polychemicals Co., Ltd.)
(A4) is an ethylene-vinyl acetate copolymer having a vinyl acetate content of 19% by weight and a melt index of 2.5 (Evaflex manufactured by DuPont-Mitsui Polychemicals Co., Ltd.). 460 (19 VA
(A5) is an ethylene-vinyl acetate copolymer having a vinyl acetate content of 19% by weight and a melt index of 15 (Evaflex manufactured by DuPont-Mitsui Polychemicals Co., Ltd.). 450 (19VA1
5MI) (product name)). (A′1) is an ethylene-vinyl acetate copolymer having a vinyl acetate content of 28% by weight and a melt index of 150 (KC-10 (28VA150MI) (trade name) manufactured by Sumitomo Chemical Co., Ltd.).

(B1) to (B6) are (B) tackifying resins: (B1) is a tackifying resin (Clealon, manufactured by Yashara Chemical Co., Ltd.) which is a partially hydrogenated petroleum resin having a softening point of 100 ° C. (B2) is a tackifying resin (Clearon M-10, manufactured by Yashara Chemical Co., Ltd.) which is a partially hydrogenated petroleum resin having a softening point of 105 ° C.
(B3) has a softening point of 125 ° C.
Resin which is a rosin ester of Arakawa Chemical Co., Ltd.
Super Ester T-125 (trade name));
(B4) is a tackifier resin (Niretz V2040HM (trade name) manufactured by Arizona Chemical Co.) which is a phenolic modified terpene having a softening point of 125 ° C; (B5) is hydrogen having a softening point of 100 ° C. Tackifying resin which is a petroleum resin not added (Yresin Chemical Co., Ltd., YSresin TO-105)
(B6) is a tackifying resin (KE-604 (trade name) manufactured by Arakawa Chemical Co., Ltd.) which is a rosin ester having a softening point of 125 ° C.

(C1) is (C) a crystalline polyethylene wax having a softening point of 100 ° C. or higher and a softening point of 136 ° C. (High Wax 400 manufactured by Mitsui Chemicals, Inc.)
P (product name)). Here, the physical properties of (A) to (C) were evaluated using the following methods. The vinyl acetate content (% by weight) was measured using a method similar to the method described in JIS K6730. The melt index (or melt flow rate) was measured using the same method as described in JIS K6730. The softening point is JIS K2
The measurement was performed using the same method as described in 207.

Example 1 Preparation of Hot Melt Adhesive An ethylene-vinyl acetate copolymer having a vinyl acetate content of 20% by weight and a melt index of 20 (Sumitate HA-20 manufactured by Sumitomo Chemical Co., Ltd. (20VA20MI))
(Trade name)) (A1): 30 parts by weight Ethylene-vinyl acetate copolymer having a vinyl acetate content of 20% by weight and a melt index of 300 (Sumitate HE-10 (20VA300M manufactured by Sumitomo Chemical Co., Ltd.)
I) (trade name)) (A2): 10 parts by weight Tackifying resin which is a partially hydrogenated petroleum resin having a softening point of 105 ° C (Clearon (C, manufactured by Yashara Chemical Company)
(learon) M-105 (trade name)) (B2): 20
Parts by weight Tackifying resin which is a phenolic modified terpene having a softening point of 125 ° C. (Niretz (Nirtz manufactured by Arizona Chemical Company)
etz) V2040HM (trade name)) (B4): 30 parts by weight Crystalline polyethylene wax having a softening point of 136 ° C (Mitsui Chemicals High Wax 400P (trade name)) (C
1): (A1), (A2), (B2),
Each material of (B4) and (C1) was charged into a container, and 17
The mixture was heated to 0 ° C., stirred for 1 hour, uniformly mixed and dissolved. To the obtained composition was added 0.2 parts by weight of a phenolic antioxidant (Sumitomo Chemical Co., Ltd. Sumilizer BP-1).
01 (trade name)), 0.2 parts by weight of a sulfur-based antioxidant (Sumitomo Chemical Co., Ltd. Sumilizer TPS (trade name)), and 0.2 parts by weight of a phosphorus-based antioxidant (Sumitomo Chemical Industries, Ltd. Sumilizer P-16 (trade name)) was added to obtain a hot melt adhesive of Example 1.

Evaluation of Hot Melt Adhesive (1) Evaluation of Softening Point of Hot Melt Adhesive The softening point of the hot melt adhesive was determined in the same manner as the method described in the R & B method (Japan Adhesive Industry Association Standard JAI 7). It measured using. The softening point of the hot melt adhesive of Example 1 was 121 ° C. The results are shown in Table 1. (2) Evaluation of Viscosity of Hot Melt Adhesive The viscosity of the hot melt adhesive was measured at 140 ° C. and 160 ° C. using a Brookfield viscometer (spindle 27).
And 180 ° C. The viscosity of the hot melt adhesive of Example 1 was 121.5 at 140 ° C.
Pa · s, 45.4 Pa · s at 18 ° C., 18
At 0 ° C., it was 19.5 Pa · s. Table 1 shows the results
It was shown to.

[0038] (3) a hot-melt adhesive kraft paper evaluation weighing about 50 g / m ² of adhesion, was coated with hot melt adhesive so that the basis weight of about 50 g / m ² at 160 ° C.. 1cm width x 4c length in the direction parallel to the coating direction
The coated kraft paper was cut out into a strip having a size of m to prepare an adhesive tape. Using the adhesive tape,
Two lead wires (each lead wire has a diameter of 0.7 mm and a length of 18 mm) of an electronic component (weighing 1.5 g) are placed in the longitudinal direction of a mount (width 2.5 cm × length 4 cm). And sandwiched vertically. At that time, the lead wire of the electronic component was sandwiched between the mount and the adhesive tape such that the distance between the portion where the lead wire protruded from the electronic component and the adhesive tape was about 7 mm.
2.9 × 10 ⁵ Pa is applied to the lead wire of the sandwiched electronic component.
A pressure of (3 kgf / cm ² ) was applied, and the sample was heated and pressed at 160 ° C. for 3 seconds to prepare a test sample.

The test sample was stored under the following various conditions: (Condition 1) Storage for 100 hours in a room at 20 ° C. and 65% humidity; (Condition 2) 70 placed in a room at 20 ° C. and 65% humidity. After storage in a dryer at 100 ° C. for 100 hours, storage in a room at 20 ° C. and 65% humidity for 12 hours; (Condition 3) After storage in a room at 60 ° C. and 90% humidity for 100 hours, in a room at 20 ° C. and 65% humidity. Stored for 12 hours.

With respect to the test samples stored under the above-mentioned conditions, the electronic parts were pulled out at a speed of 20 mm / min, and the force at that time was measured to determine the adhesive strength. The adhesive strength of the hot melt adhesive of Example 1 was 22.
9N (2.33 kgf), 31.7 N under condition 2
(3.23 kgf), and 15.0 N under condition 3
(1.53 kgf). The results are shown in Table 1.

(4) Evaluation of Heat Resistance of Hot Melt Adhesive The test sample prepared in the evaluation of the adhesive strength of the hot melt adhesive was stored in a room at 20 ° C. and a humidity of 65% for 12 hours. Was used for evaluation of heat resistance.
The test sample stored in the room at 20 ° C. and a humidity of 65% for 12 hours was hung in a dryer at 80 ° C. At that time, the test sample was hung so that the longitudinal direction of the test sample was vertical, and thus the lead wires of the electronic components were horizontal. After storing for 2 hours in that state, it was observed whether the electronic component had dropped from the adhesive sample. Two test samples were evaluated. The heat resistance of the hot-melt adhesive is as follows: the electronic components did not drop at all for the two test samples; ○ the electronic component fell for one test sample; and Δ both the electronic components dropped. Is indicated by x. The heat resistance of the hot melt adhesive of Example 1 was ○. The results are shown in Table 1.

Examples 2 to 6 For Examples 2 to 6, the same method as described in Example 1 was used except that the materials used in Example 1 were changed to the materials and amounts shown in Table 1. Examples 2 to 6
Hot melt adhesive was obtained. Using the same method as that described in Example 1, the hot melt adhesives of Examples 2 to 6 were evaluated. The results are shown in Table 1.

Comparative Example 1 Comparative Example 1 was performed in the same manner as in Example 1 except that the materials used in Example 1 were changed to the materials and amounts shown in Table 1.
A hot melt adhesive of Comparative Example 1 was obtained using the same method as in Example 1. Using the same method as that described in Example 1, the hot melt adhesive of Comparative Example 1 was evaluated. The results are shown in Table 1.

Comparative Example 2 In Comparative Example 2, the materials used in Example 1 were changed to the materials and amounts shown in Table 1, and 0.2 parts by weight of a phenolic antioxidant (Sumitomo Chemical Industries, Ltd.) Sumilizer BP-101 (trade name)), 0.2 parts by weight of a sulfur-based antioxidant (Sumitomo Chemical Co., Ltd. Sumilizer T
PS (trade name)) and 0.5 parts by weight of a phenolic antioxidant instead of 0.2 parts by weight of a phosphorus-based antioxidant (Sumitomo Chemical Co., Ltd. Sumilizer P-16 (trade name)) (Sumitomo Chemical Industries, Ltd. Sumilizer BP-101
A hot melt adhesive of Comparative Example 2 was obtained using the same method as in Example 1 except that (trade name)) was used. Example 1
The hot melt adhesive of Comparative Example 2 was evaluated by using the same method as described in the above section. The results are shown in Table 1.

[0045]

[Table 1] a) The unit of each material is parts by weight. b) The unit of the softening point is ° C. c) The unit of viscosity is Pa · s. d)
The unit of the adhesive force is N. The values in parentheses are values when the unit is kgf.

[0046]

Since the present invention is configured as described above, it has the following effects. The hot melt adhesive of the present invention has (A) a vinyl acetate content of 10% by weight.
As described above, the ethylene-vinyl acetate copolymer is 25% by weight or less, (B) a tackifying resin, and (C) a softening point of 100%.
The wax contains a wax of at least 180 ° C and has a viscosity of 180 ° C of 10
１００100 Pa · s, so that compared to conventional hot melt adhesives, it has a high heat resistance, a low coating temperature, a low viscosity during coating, and a high adhesive strength. , At least one characteristic is improved, and the balance of the characteristics is improved.

Further, the hot melt adhesive of the present invention
Since (B) the tackifier resin is contained in an amount of 150 to 200 parts by weight with respect to the total (100 parts by weight) of the (A) ethylene-vinyl acetate copolymer and the (C) wax, a conventional hot melt adhesive is used. In comparison, furthermore, high heat resistance,
Low coating temperature, low coating viscosity,
And at least one property of high adhesion is better, and the balance of properties is better.

Furthermore, by using the hot melt adhesive of the present invention for an adhesive tape, the heat resistance is higher and the uniformity of the coated surface of the base material is higher than that of an adhesive tape using a conventional hot melt adhesive. Of high and high adhesive strength,
An adhesive tape having at least one property improved and a better balance of properties can be produced.

Further, by using the hot melt adhesive of the present invention for an electronic component holding tape, the heat resistance and the adhesive strength are higher than those of a conventional electronic component holding tape using a hot melt adhesive. An electronic component holding tape in which at least one characteristic is improved, that is, the alignment accuracy of the electronic component is high due to the high uniformity of the coated surface of the base material, and the characteristic is well-balanced. .

Claims (4)

[Claims] (A) a vinyl acetate content of at least 10% by weight;
25% by weight or less of an ethylene-vinyl acetate copolymer, (B) a tackifying resin, and (C) a wax having a softening point of 100 ° C or more,
A hot melt adhesive having a viscosity at 180 ° C. of 10 to 100 Pa · s. 2. The composition of (B) with respect to the total (100 parts by weight) of (A) the ethylene-vinyl acetate copolymer and (C) wax.
2. The hot melt adhesive according to claim 1, comprising 150 to 200 parts by weight of a tackifier resin. 3. The electronic component holding tape according to claim 1, wherein
2. The hot melt adhesive according to 1. 4. An adhesive tape produced by using the hot melt adhesive according to claim 1.