JPH08281764A - Hot melt adhesive block obtained using a novel method of making hot melt adhesive - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] Efficient manufacturing method of hot melt adhesive that has stickiness or takes a long time for stickiness to disappear, and it is industrial waste as before. (EN) A hot-melt adhesive block capable of obtaining heating stability and coating stability when the hot-melt adhesive is used, without the occurrence of heat. [Structure] In a double-column hot-melt adhesive block, the hot-melt adhesive for the core layer has an ABA-type styrene block copolymer as a base polymer and has a normal tackiness or loses its tackiness. It takes a long time for the hot melt adhesive for the skin layer to be styrene 2
15 to 50% by weight of ABA type styrene block copolymer of 5% by weight or more, styrene type, hydrogenated petroleum type and rosin ester type of 30 to 60 having a softening point of 120 ° C. or more.
%, Paraffinic, naphthenic oils, mixtures thereof from 5 to 35% by weight.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an adhesive for an adhesive tape,
The present invention relates to a method for producing a hot-melt adhesive (hereinafter abbreviated as HM) that is used for assembling a paper diaper, for attaching a decorative cloth to an interior panel, or the like. The present invention relates to a method for producing an HM that requires a long time for the tackiness to disappear.

[0002]

2. Description of the Related Art Conventionally, an HM which has stickiness or which requires a long time for the stickiness to disappear, has a block-like HM with a releasability in order to prevent self-adhesion during manufacturing, storage, transportation and the like. Products were manufactured by wrapping with material. As a manufacturing method using such a packaging material, a method of folding a PET film or paper treated with silicone into a box shape, and immediately or by inserting it into a metal tray and pouring molten HM, A method has been adopted in which a thick polypropylene sheet subjected to silicone treatment on the inner surface side is molded into a tray shape and the molten HM is directly poured into the tray shape.

However, in the above-mentioned conventional method, it is necessary to peel off the packaging material and dispose of it when using the packaged HM, which requires complicated labor and may cause environmental pollution due to the waste. . Therefore, from the viewpoint of resource saving, environmental protection, and improvement of workability during use, HM that does not use these containers has stickiness with a thin polyolefin film or powder, or it takes a long time for the stickiness to disappear. The following various methods (1) to (5) have been proposed in which the above-mentioned polyolefin film or powder is wrapped in and melted in a melting tank without being peeled off at the time of use.

(1) Japanese Unexamined Patent Publication No. 63-39977: A known molding die is sprayed with a non-adhesive material such as paraffin or olefins in a molten state, and molten H having adhesiveness to the molding die.
A method of pouring M to eliminate surface tackiness.

(2) JP-A-6-270901: A method in which a known metal container is laid with a polyolefin film of 20 to 50 microns for packaging and then a molten HM having an adhesive property is poured.

(3) JP-A-6-270902: Instead of a known metal container, a first layer (outer surface side) made of polyolefin and a second layer made of a low melting point plastic having good compatibility with HM. (Inner surface side) A method of pouring molten HM having adhesiveness into a molded container composed of (inner surface side).

(4) A product sold under the trademark "Zeropack", in which an adhesive HM is coated with a non-adhesive polyolefin-based material and a small HM of 5 to 10 g / block
How to block.

(5) Japanese Unexamined Patent Publication No. 5-310962: A known method is to package a pressure-sensitive adhesive composition that causes cold-flowing with a film of a styrene block copolymer system such as SBS or SIS. ing.

(6) However, the above (1) to (5)
The method has the following recognized drawbacks.
In the method (1), tackiness appears on the surface within several days during storage, and the blocks are re-fused together. There are drawbacks such as spraying a non-adhesive material on the mold and taking steps to remove the HM block from the mold.

In the methods (2), (3) and (4), a polyolefin is used as a non-adhesive material for a packaging film, a container or an outermost package, and in any case, these compositions are melted once. When mixed with a sticky HM encapsulated therein, it has the property of clogging filters and nozzles of conventional manufacturing machines under certain manufacturing conditions due to poor heating stability. In addition, even the addition of only a few percent by weight of polyolefin to an HM having an adhesive property has a negative effect on the adhesiveness to an adherend and the adhesive performance of the HM having an adhesive property. Indicated

The method (5) is a packaging film using a styrene block copolymer as a base polymer, which has good heat stability, but requires a lot of time and labor for the production of the packaging film, and the packaging film has a manufacturing process. , High viscosity (163
It is inevitable that the viscosity will change from about 40 Ps to 500 Ps at ℃, and the melt viscosity of HM with general adhesion (16
Since there is a large difference between approximately 1 P · s and less than 40 P · s at 3 ° C., it adversely affects the uniformity of the applied state during use.

[0012]

Therefore, the present invention solves the above-mentioned problems of the prior art and has tackiness or loses tackiness from the viewpoints of resource saving and environmental conservation. An object of the present invention is to eliminate the cheekiness during the manufacturing process of HM that requires a long time and during use, and to obtain the heating stability and coating stability during HM use. In order to solve the above problems, the present invention employs the following means.

[0013]

That is, the HM according to the present invention
The block is a double columnar HM block, and the HM for the core layer has an ABA-type styrene block copolymer as a base polymer and has an adhesive property in a normal state, or an HM that requires a long time for the adhesive property to disappear. The skin layer HM used is 15 to 50% by weight of an ABA type styrene block copolymer having 25% by weight or more of styrene and a softening point of 120 ° C.
An HM comprising 30 to 60% by weight of a resin appropriately selected from the above styrene type, hydrogenated petroleum type and rosin ester type, and 5 to 35% by weight of paraffin type or naphthene type oil or a mixture thereof, and having a core layer. The HM for the core layer and the HM for the skin layer are extruded into double pillars in water using a co-extrusion die, using an HM that has the same melt viscosity and softening point values as those of the HM for use in the normal state, and is cut using a coextrusion die. However, it is an HM block having almost no surface tackiness obtained by coating the end portion with HM for a skin layer.

The core layer HM has an adhesive property in a normal state conventionally used for an adhesive of an adhesive tape, an assembly for producing a paper diaper, and a decorative cloth for an interior panel, or The HM that requires a long time for the tackiness to disappear is the HM of the center portion of the coextrusion die, that is, the portion extruded from the core side, and the outer diameter dimension is preferably about 30 mm to 60 mm. HM for core layer
The base polymers of SBS, SIS and SEB are generally
ABA type block copolymers such as S and SEPS are used. In addition to these base polymers, various tackifiers such as rosin ester, terpene resin, C5 or C9 petroleum resin, hydrogenated resins thereof, various plasticizers such as paraffinic or naphthenic oil, polybutene, polyisobutylene, etc. According to antioxidants,
An HM that is a mixture of various additives such as an inorganic filler and a colorant and that has adhesiveness in the normal state or that requires a long time for the adhesiveness to disappear is used as the HM for the core layer.

The skin layer HM is a HM of a portion extruded from the outer portion of the coextrusion die for the purpose of coating the core layer HM, and is not tacky in a normal state or loses tackiness after melt extrusion. An HM with a very short time-to-use must be used as the HM for the skin layer. In the HM extruded into water in the form of a double column from the coextrusion die, the HM for the skin layer is first cooled and solidified in water. The core layer HM, which has a low solidification rate and solidifies later, flows into the HM block by the pressure during cutting and is covered with the skin layer HM up to the cut end portion, so that the end portion has little tackiness. The HM for the skin layer is put into the melting tank of the HM coating machine in an integrated state with the HM for the core layer, and generally 120 to 180 ° C.
It is melted at a moderate temperature. At this time, since the normal melting tank does not have a stirring device for mixing, the skin layer HM has a similar melt viscosity at the set melting temperature to the core layer HM, preferably the core layer HM. Normally 1P at 120 ° C
+ 20% to the melt viscosity of 30 P · s from s to 180 ° C
To -20%, and the softening point is about the same, preferably + 10 ° C to -10 ° C with respect to the softening point of the core layer HM of usually 60 ° C or higher. Further, as in most of the above-mentioned conventional techniques, as the skin layer HM, when the ABA type styrene block copolymer has poor compatibility with the core layer HM which is the base polymer, even if the melt viscosity and the softening property are softened. Points are HM for core layer
Even if it is about the same as, the troublesome filter and nozzle clogging that occurs when used in combination with the HM coating machine,
It is essential that the compatibility with the HM for the core layer is good because other harmful effects occur.

The composition of the HM for the skin layer is appropriately selected from 15 to 50% by weight of ABA type styrene block copolymer containing 25% by weight or more of styrene and styrene type, hydrogenated petroleum type and rosin ester type having a softening point of 120 ° C. or more. 30 to 60% by weight of selected resin, 5 to 35% by weight of paraffinic or naphthenic oils or mixtures thereof of H
It must be an M composition. The use of ABA type styrene block copolymers containing less than 25% by weight of styrene and styrene-based, hydrogenated petroleum-based and rosin ester-based resins having a softening point of less than 120 ° C.
It is not suitable because it causes a problem that adhesiveness occurs. Also, oils other than paraffinic and naphthenic oils and plasticizers such as polybutene have poor compatibility with the core layer HM and cause problems such as stickiness of the skin layer HM, and paraffin. If the oil content of the system-based or naphthene-based oil is more than 35% by weight, the problem that the time until the tackiness of the skin layer HM disappears becomes long occurs.

Examples of ABA type styrene block copolymers containing 25% by weight or more of styrene include Vectors 4211D, 4411D and 4261D manufactured by Dexico Chemical. Also, as a styrene resin having a softening point of 120 ° C. or higher,
Hercules Endex 120, 155, 16
0 and Picotex 120, Picolastic D-12
There is 5 mag. Hydrogenated petroleum-based resins and rosin ester-based resins having a softening point of 120 ° C. or higher are Alcon P-1 of Arakawa Chemical Co., Ltd.
25, P-140, Pencel C, paraffinic oil is Esso Petroleum Cristol 70, 350, naphthenic oil is Shell Petroleum Shelf Rex 371JY, 37
There are 1N etc.

In addition to the above essential components, the HM for the skin layer of the present invention is used for the core layer in order to further improve various properties such as thermal stability at the time of melting, weather resistance and workability, if necessary. H
An antioxidant, an inorganic filler, a colorant, etc., which are also used as an additive component of M, are added. A mixture obtained by mixing the above components in a predetermined mixing ratio is melt mixed according to a conventional method to obtain a uniform mixed composition similar to the core layer HM. The core layer HM and the skin layer HM are melted in separate melting devices according to a conventional method, and then extruded into water into a double columnar shape using a coextrusion die.

Another feature of the manufacturing method of the present invention is that a manufacturing method is possible in which the HM extruded into water in the form of a double columnar shape is simultaneously molded by a caterpillar type drawing machine. In the conventional take-up machine, H is extruded from the co-extrusion die.
After M was cooled, it was a conventional method to take it off with a take-up roll so as to maintain the shape as it was. After that, a manufacturing method of cutting into an appropriate size with a cutting machine has been performed. The production method in which the caterpillar type take-up machine of the present invention is used to perform molding simultaneously with taking-up is H
When the HM for the skin layer of M is solidified and the HM for the core layer is melted, a columnar HM is pressed while applying pressure to the columnar HM to take it off and cool it. It is an HM block obtained using the manufacturing method.

The weight of the HM block is preferably about 3 to 5000 g so that it can be easily melted in the melting tank of the HM coating machine. The weight ratio of the HM for the core layer to the HM for the skin layer is adjusted depending on the intended use, and it is not particularly limited, but usually a range of 100: 0.2 to 100: 50 is preferable. Further, it is possible to add a part of the ABA type styrene block copolymer among the HM components for the core layer to the components of the HM for the skin layer.
If the ABA type styrene block copolymer of 25% by weight or more of styrene exceeds the range of 15 to 50% by weight, a problem occurs.

[0021]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. 1. Preparation method of HM composition 500 g of a mixture compounded in a predetermined ratio was charged into a 1000 cc heating kneader, and the mixture was melt kneaded at 180 ° C. for 2 hours for adjustment. In addition, each of the double columnar extruded products was made into an HM block of about 100 g by the production method of the present invention described above.

2. The raw materials used in Examples and Comparative Examples, as well as their compositions and properties, are shown in Table 1. All% shown in the properties represent% by weight in the composition.

[0023]

[Table 1]

3. Test Method (1) Melt Viscosity Melt viscosity at 180 ° C. was measured according to the melt viscosity measuring method of JIS K-6862HM.

(2) Softening point The softening point of the ring and ball method was measured according to the softening point measuring method of JIS K-6863HM.

(3) Peeling adhesiveness HM melted at 180 ° C. is applied to an aluminum plate to a thickness of about 100 μ, and after 10 minutes, laminated with a polyester film,
The test piece adhered by press-fitting three times with a hand roller of 5 kg was allowed to stand at 20 ° C. for 72 hours, and then the peel strength of 180 ° was measured using an autograph tensioner at a pulling speed of 300 mm / min.

(4) Surface tackiness HM melted at 180 ° C. is applied to two aluminum plates to about 100 μm.
And then immediately cooled in water at 20 ° C, and then the HM coated surfaces were put together and the load of 100g / cm was applied.
After standing at 0 ° C. for 72 hours, the state was confirmed. The state of peeling without resistance was defined as no surface tackiness.

(5) Adhesion disappearance time HM melted at 180 ° C. is applied to two aluminum plates to about 100 μm.
Was applied to a thickness of 10 ° C., immediately cooled in water at 20 ° C., taken out at intervals of 5 seconds, and when the HM-coated surfaces were strongly adhered to each other immediately, the cooling time that could be easily peeled off was taken as the tackiness disappearance time.

(6) Compatible core layer HM and skin layer HM in a ratio of 100: 5,
A single columnar HM block extruded and cut to a diameter of 30 mm, approximately 100 g each, was placed in a 500 cc beaker for 18
After leaving it in a dryer at 0 ° C. for 60 minutes, the beaker was taken out and the state when the molten HM was poured out was observed. The uniform state was regarded as good compatibility, and the non-uniform state was regarded as poor.

(7) Storability One piece is a double columnar H extruded into a diameter of 30 mm of about 100 g.
Pack M blocks in approximately 100 cardboard boxes at 40 ° C
After being left in the dryer for 30 days, it was taken out and the state was observed. The state in which each block can be taken out without resistance was defined as good storability.

Examples 1 to 6 are shown in Table 2.

[0032]

[Table 2]

Comparative Examples 1 to 6 are shown in Table 3.

[0034]

[Table 3]

It will be apparent to those skilled in the art that the above examples are made for purposes of illustration and that proportions, procedures and materials may be varied without departing from the scope of the invention as defined in the claims. Is.

[0036]

EFFECTS OF THE INVENTION According to the present invention, an HM that has a tackiness in the normal state or takes a long time for the tackiness to disappear.
It is possible to provide an HM block having a good compatibility even when it is re-melted and having no surface tackiness even when it is re-melted. In addition, as described in the prior art, since no packaging material is used, there are resource saving and environmental conservation effects.

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Claims (2)

[Claims] 1. A double columnar hot-melt adhesive block, wherein the hot-melt adhesive for core layer has an ABA-type styrene block copolymer as a base polymer and has a normal tackiness or loses the tackiness. A hot melt adhesive that requires a long time to cure is used. The hot melt adhesive for the skin layer is 15 to 50% by weight of ABA type styrene block copolymer containing 25% by weight or more of styrene and styrene having a softening point of 120 ° C. or more. System, hydrogenated petroleum system, and rosin ester system resin selected from 30 to 60% by weight, paraffinic or naphthenic oil, or
A hot-melt adhesive containing 5 to 35% by weight of a mixture thereof and having a melt viscosity and a softening point of the same degree as those of the hot-melt adhesive for the core layer, which is normally non-tacky, is used. Using a hot-melt adhesive for core layer and hot-melt adhesive for skin layer using a co-extrusion die, extruded and cut into water into a double columnar shape, and the end is almost covered with hot-melt adhesive for skin layer. The resulting hot melt adhesive block without surface tack. 2. A hot-melt adhesive having no surface tackiness according to claim 1, which is obtained by a method in which a hot-melt adhesive extruded in water into a double columnar shape is simultaneously taken up by a caterpillar type take-off machine. Agent block.