JPH06329999A - Self-adhesive, self-adhesive tape, and self-adhesive sheet - Google Patents

Abstract

PURPOSE:To provide a self-adhesive tape or sheet which has stickiness at normal temp. and reacts after bonded to become heat-resistant and to enable the tape or sheet to be stored long without causing change in quality with time. CONSTITUTION:A self-adhesive tape is produced by forming a reactive self-adhesive hot-melt compsn. comprising an isocyanate-ended polyurethane prepolymer into a thin film, applying the film to a substrate, and winding the resulting coated substrate together with a separator around a core tube. A self-adhesive sheet is produced by stacking the coated substrates with the separator inserted between each of the substrates. Or the separator may directly by coated with the film of the hot-melt compsn. and wound to a core tube to give the self-adhesive tape or sheet. The tape or sheet is packaged with a moistureproof material and stored.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive tape or sheet having an adhesive property at room temperature in the initial state and having heat resistance after being bonded by being hardened by moisture in the air or an adherend. It is a thing.

[0002]

2. Description of the Related Art Generally, an adhesive tape or an adhesive sheet does not require special equipment such as an applicator and is therefore widely used for simple and light adhesion in various fields. As the pressure-sensitive adhesive used in the pressure-sensitive adhesive tape or the pressure-sensitive adhesive sheet, various types of rubber-based pressure-sensitive adhesives such as natural rubber, butyl, SBR, etc., acrylic-based or hot-melt-based adhesives are used.

[0003]

However, the conventional pressure-sensitive adhesive tape or pressure-sensitive adhesive sheet generally uses a rubber or resin having a relatively low molecular weight, or uses a large amount of a plasticizer, in principle that it has adhesiveness at room temperature. Therefore, the heat resistance was poor. Conversely, if the molecular weight of the base rubber and resin is increased or the amount of the plasticizer is decreased in consideration of heat resistance, as a result, the tackiness is impaired and it becomes unsuitable for practical use.

When a cross-linking component is added during compounding, it has tackiness in the initial stage, but due to a change with time, the reaction proceeds during storage, the tackiness decreases, and finally the tackiness disappears. It becomes unsuitable for practical use.

The present invention solves the above-mentioned drawbacks and provides an adhesive tape or an adhesive sheet which has adhesiveness at room temperature and which reacts after adhesion and has good heat resistance, and changes the adhesive tape or adhesive sheet with time. The purpose is to enable long-term storage without

[0006]

DISCLOSURE OF THE INVENTION The present invention provides an isocyanate at the molecular end of a polyurethane skeleton obtained by adding a diisocyanate to a polyol component containing a base resin and a tackifying resin and a terminal hydroxyl group hydrocarbon type polyol. A reactive adhesive hot melt composition of a prepolymer having a nato group is formed into a thin film. This reactive adhesive hot melt formed into a thin film is applied to a base material and wound around a core together with a separator to obtain an adhesive tape. Alternatively, the pressure-sensitive adhesive sheets are laminated with a separator interposed therebetween. Alternatively, the reactive adhesive hot melt composition formed into a thin film is directly coated on a separator to obtain an adhesive tape or an adhesive sheet. In addition, these adhesive tapes or sheets are stored in a packaging material having a moisture-proof function.

The structure of the present invention will be described below.

(1) Base resin As the base resin, isoprene-styrene block copolymer (SIS), butadiene-styrene block copolymer (SBS) and its hydrogenated polymer (SEBS).
・ SEPS), ethylene-vinyl acetate copolymer (EV
A), ethylene-acrylate copolymer (EEA), atactic polypropylene, thermoplastic linear polyester, and the like, but SIS is preferable in consideration of adhesiveness, and SEPS is particularly preferable when heat resistance is required.

(2) Tackifying Resin Examples of the tackifying resin include terpene resins (terpene resin, terpene phenol resin, aromatic modified terpene resin, hydrogenated products thereof, etc.), petroleum resin (C ₅ aliphatic resin). , C ₉ aromatic, C ₉ aliphatic, hydrogenated products thereof, etc.),
It can be widely used for rosin ester resins (rosin ester, hydrogenated rosin ester, etc.), coumarone indene resin, styrene resin, etc. In the reactive adhesive hot melt composition of the present invention, the softening agent (aromatic process oil, fluid) used in the conventional hot melt adhesive is used within a range in which the object of the present invention can be achieved. Paraffin and the like), waxes (low molecular weight polyethylene, polymerized wax and the like), and others (inorganic filler, colorant, antiaging agent and the like) can also be added.

(3) Polyol The terminal hydroxyl group hydrocarbon type polyol having good compatibility with the base resin and the tackifying resin is a hydrocarbon type polyol having a hydrocarbon skeleton and having a hydroxyl group at the end, and is a heavy hydrocarbon of butadiene. Combined terminal hydroxyl group polybutadiene,
Typical examples include polyisoprene having a terminal hydroxyl group, which is a polymer of isoprene, and used. Further, hydrogenated ones may be used to eliminate the above-mentioned hydrocarbon double bond.

(4) Diisocyanate As the diisocyanate which reacts with the above diol,
Aliphatic, alicyclic or aromatic diisocyanates such as 2,4 / 2,6 tolylene diisocyanate, 4,4 'diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate and xylylene diisocyanate Although those normally used for urethane resins such as nato compounds can be used, 4,4'-diphenylmethane diisocyanate is preferable in consideration of the moisture curing rate, industrial price, safety and hygiene. A urethane prepolymer having isocyanate groups at both ends is obtained by addition reaction of the above-mentioned polyol component having hydroxyl groups at both ends and excess diisocyanate by a conventional method. In this case, the content of the isocyanate group in the urethane polymer is preferably 1.5% by weight to 4.0% by weight, and when the content is less than 1.5% by weight, the viscosity increases as the molecular weight of the prepolymer increases. Rises and becomes unsuitable for use. On the other hand, if the content exceeds 4.0% by weight, the amount of free polyisocyanate increases, the performance deteriorates due to the inclusion of bubbles during curing, and the viscosity also sharply decreases and the initial adhesive strength decreases. .

(5) Sub-material As the sub-material used in the present invention, a material having a water content of 1% or less is used. It is preferable to use a plastic material that does not absorb water. As the tape-shaped base material or the sheet-shaped base material, various materials such as non-woven fabric, films such as polyester and polypropylene, polyethylene, urethane foam can be used. Considering the adhesiveness of
A polyester-based nonwoven fabric of 200 g / square meter is preferable. Further, as the separator, films such as polypropylene and polyester which have been subjected to release treatment are used.
Considering the heat resistance during application of the reactive adhesive hot melt composition, a polyester film subjected to a release treatment is preferable. The base material may be omitted if necessary. As a core for a pressure-sensitive adhesive tape, a general paper tube is not suitable for use because it has hygroscopicity. Again, this is a resin-impregnated paper tube with a water content of 1% or less, rigid PVC
A plastic tube such as a pipe is preferred.

(6) Packaging material An aluminum bag coated with polyethylene on the inner surface in order to block moisture from the outside in consideration of stability during storage,
A polyester bag having a water-proof inner surface or a sealable metal container is preferable.

Next, the production of the reactive adhesive hot melt composition and the application of the tape or sheet will be described.
The reactive adhesive hot melt composition has a temperature of 180 to 200 ° C.
About 90 minutes, the thermoplastic rubber base of (1) above,
After kneading the tackifying resin of (2), the diol of (3) and the process oil with a kneader until uniform, the mixture is put into a reaction kettle and the diisocyanate of (4) is added at 80 to 120 ° C. Then, the reaction is performed in a nitrogen gas atmosphere to obtain a reactive adhesive hot melt composition. This reactive adhesive hot melt composition is put into an applicator at 100 to 120 ° C. and melted, then discharged from a T-die and coated on a tape-shaped substrate or sheet-shaped substrate, and a separator is put together to form a pressure-sensitive adhesive tape or pressure-sensitive adhesive sheet. To get Also, if necessary, the base material may be omitted and it may be applied directly on the separator without causing any trouble. The types of base material, separator, and winding core must naturally have a water content of 1% or less. The thickness of the adhesive layer is 50 μm
Adjust appropriately within the range of 5 mm. In order to improve the adhesiveness to the rough surface, 100 μ or more is preferable.

[0015]

The initial adhesiveness at room temperature when the pressure-sensitive adhesive of the present invention is adhered is strong, and it reacts with the humidity in the air or the adherend over time to improve the cohesive force. Have sex. In other words, due to the strength of the initial adhesiveness, it can be easily attached by just pressing, like ordinary adhesive tapes or adhesive sheets, and the heat resistance and creep resistance are improved over time like a heat-resistant adhesive, making it durable. Have sex. When the adhesive tape or adhesive sheet is stored in a packaging material having a moisture-proof function, the moisture from the outside is blocked, and the adhesive tape or the adhesive sheet has excellent long-term storage stability without reacting with moisture.

[0016]

【Example】

Example 1. Thermoplastic block copolymer: (SIS
Nippon Zeon. After adding 135 parts by weight of terpene resin (Yasuhara Chemical.TO-105) to 100 parts by weight of Quintac 3435) in a horizontal kneader and kneading at 180 ° C. for 60 minutes, polybutadiene having a terminal hydroxyl group (Idemitsu Chemical.R-45H
T) (75 parts by weight) and aromatic process oil (Idemitsu Kagaku. NS-100) (20 parts by weight) were added, and the mixture was further kneaded for 30 minutes until uniform. 100 parts by weight of this mixture was placed in a reaction kettle and melted at 120 ° C., then 16 parts by weight of diphenylmethane diisocyanate was added from a charging port and reacted for 1 hour in a dry nitrogen gas atmosphere to obtain an isocyanate content of 3.5 parts by weight. %, Melt viscosity at 120 ° C. 7000 c
A reactive adhesive hot melt composition of ps (Brookfield type viscometer) was prepared.

Example 2. Example 1 except that the amount of diphenylmethane diisocyanate added was 11 parts by weight. Is carried out in the same manner as above, but with an isocyanate content of 2.3% by weight, 120
A reactive adhesive hot melt composition having a melt viscosity of 19000 cps (Brookfield type viscometer) in ° C was prepared.

Comparative Example 1. Thermoplastic block copolymer: (SIS Nippon Zeon. Quintac 3435) 1
To 100 parts by weight of terpene resin (Yasuhara Chemical. TO-10
5) 135 parts by weight were put into a horizontal kneader and kneaded at 180 ° C. for 60 minutes, followed by aromatic process oil (Idemitsu Kagaku.
S-100) (95 parts by weight) was added, and the mixture was further kneaded for 30 minutes until uniform, and this was used as a comparative sample of the above reactive adhesive hot melt composition.

Each physical property was evaluated by the following measuring methods. (1) Loop Tack The pressure-sensitive adhesive prepared under the above conditions was pressed to a thickness of 200μ, and a sample adhered to 70μ of kraft paper was taken into a width of 1 inch x length of 12 inches, and the adhesive surface was placed outside to form a loop. Set in the tensile tester. Attach the glass plate horizontally to one of the grips. The loop-shaped test piece was brought into contact with the glass plate and immediately pulled at a speed of 200 mm / min, and the load when the glass plate and the adhesive surface were separated was taken as the loop tack value. (2) Initial tensile shear strength The pressure-sensitive adhesive prepared under the above conditions was pressed to a thickness of 200μ, cut into 1-inch width, and the plywood plates were pressed together. Shear peel strength was measured. (3) Shear peeling strength after curing for 1 week The sample bonded by the method of (2) is 20 ° C x 60% R
After leaving for one week in the H thermostat, the measurement was performed in the same manner as in (2). (4) Temperature rising softening point temperature Using the same sample as in (3), after suspending various loads,
The temperature was raised at a rate of 2 ° C./5 min and the temperature when the load dropped was measured. (5) Finger touch tack The sample is touched with finger at 20 ° C. × 60% RH, and the degree of adhesion is indicated by ○ and ×. (○: With tack ×: Without tack)

Table 1. Example 1. , 2. And Comparative Example 1. Performance of

[Table 1] Table 2. Time-dependent behavior of shear strength after adhesion of Example adhesives

[Table 2] The reactive adhesive hot melt composition according to the present invention has adhesiveness in the initial stage and high heat resistance after aging.

Example 3. Example 1 above. The reactive adhesive hot-melt composition prepared in 1. is charged into an applicator at 120 ° C., melted, and then discharged from a T-die and coated on a polyester separator which has been subjected to a mold release, and a span which is a tape-shaped substrate is coated thereon. An adhesive tape is obtained by combining the bonds (polyester non-woven fabric: basis weight of 17 g / square meter), further coating the tape-shaped substrate, and combining the separators. (Thickness of adhesive: 150 μm coated on each of the upper and lower surfaces) A hard PVC pipe was cut into an appropriate width for the core.

Comparative Example 2. Example 3 above. An adhesive tape was produced under the same conditions as above. However, both sides of release paper (water content about 10%) are used as a separator,
The release paper was conditioned in a drying oven so that the water content was 1% and 5%.

Comparative Example 3. Example 3 above. An adhesive tape was produced under the same conditions as above. However, the moisture content of the core is 10%
The paper tube of was used. Example 3 above. Comparative Example 2. , 3. The various adhesive tapes were put in an aluminum bag treated with polyethylene on the inner surface, filled with nitrogen, sealed by heat and stored.

Comparative Example 4. Example 3. An adhesive tape was produced under the same conditions as in 1. and left indoors without using a protective bag.

The time-dependent change behavior of the sample produced under each of the above conditions was confirmed (curing was performed at 20 ° C. × 60% RH). Behavior of various samples over time

[Table 3] Decrease in tackiness is seen in all samples that are left in the room without using a separator / paper tube that contains water and not put in a protective bag, but the decrease in tackiness decreases as the water content decreases.

[0026]

The initial tackiness at room temperature when the pressure-sensitive adhesive tape or sheet of the present invention is bonded shows a strong tackiness as can be seen from the loop tack, and as shown in Table 2, it can be seen in the air or in the air over time. It reacts with the moisture of the adherend to improve the cohesive force, and has heat resistance close to that of a cross-linking reaction type adhesive.
That is, it is possible to simply attach the tape like a general adhesive tape or adhesive sheet simply by pressure bonding, and the effect of improving the heat resistance and creep resistance over time like a heat resistant adhesive and having durability is achieved. is there. Moreover, since the adhesive tape or the adhesive sheet is put in a packaging material having a moisture-proof function for storage, it retains strong adhesiveness without reacting with moisture,
Can withstand long-term storage.

Therefore, the pressure-sensitive adhesive tape or sheet of the present invention is suitable for various applications such as automobiles, electric appliances, construction, civil engineering, construction equipment, and woodworking, especially for parts requiring heat resistance. Since it is a form and does not require special equipment, it has the advantage that it does not select the processing site such as on-site construction and that it does not show the influence of pollution on the environment.

Claims (6)

[Claims] 1. A pressure-sensitive adhesive material comprising a reactive pressure-sensitive hot melt composition formed into a thin film, wherein a prepolymer as a main component has an isocyanate group at a molecular end of a polyurethane skeleton. 2. An adhesive tape obtained by applying the adhesive material according to claim 1 to a tape-shaped substrate having a water content of 1% or less, and winding this around a core together with a separator having a water content of 1% or less. 3. An adhesive tape obtained by applying the adhesive material according to claim 1 to a separator having a water content of 1% or less, and winding this around a winding core. 4. A pressure-sensitive adhesive sheet obtained by applying the pressure-sensitive adhesive material according to claim 1 onto a sheet-shaped substrate having a water content of 1% or less, and stacking a plurality of the sheets with a separator having a water content of 1% or less. 5. A pressure-sensitive adhesive sheet obtained by applying the pressure-sensitive adhesive according to claim 1 to a separator having a water content of 1% or less, and successively stacking this so that the pressure-sensitive adhesive and the separator are in contact with each other. 6. A pressure-sensitive adhesive tape or sheet obtained by storing the pressure-sensitive adhesive tape or sheet according to claim 2 in a moisture-proof packaging material.