JPS6254123B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel method for producing a hydrocarbon resin, and more particularly, a method for producing a novel hydrocarbon resin derived from 1,3-pentadiene, diisobutylene, α-methylstyrene, and optionally 1,3-butadiene. Regarding. Conventionally, methods for producing tackifier resins by cationic polymerization of monomer mixtures containing 1,3-pentadiene as a main component have been actively researched; for example, 1,3-pentadiene, 2-methyl-
Method for copolymerizing 2-butene, dicyclopentadiene and α-methylstyrene (Japanese Patent Application Laid-Open No. 48-80195
No.), Method of copolymerizing α-methylstyrene into a mixture of a monoolefin, a diolefin, and a cyclodiene having 5 carbon atoms (French Patent No. 2144317), 1,
A method for copolymerizing 3-pentadiene, cyclopentene and diisobutylene (Japanese Patent Publication No. 50-29951),
1,3-pentadiene, cyclopentene and α-
Method for copolymerizing methylstyrene (Special Publication 1973-
47835) are known. By combining 1,3-pentadiene and a specific comonomer in this way, the performance of the resulting resin can be greatly improved; in particular, the resin obtained by the latter two methods is - It has a lower melt viscosity than pentadiene homopolymers as well as resins obtained by the first two methods, has excellent compatibility with rubber and resins, and has excellent tackiness when used in pressure-sensitive adhesives and hot-melt adhesives. Various rubber-based adhesives,
It is attracting attention as a material that can replace rosin resins and terpene resins in fields such as hot melt adhesives and welding traffic paints. However, even with these improved resins, they still have some difficulty in terms of initial adhesive strength (tackiness) when used as adhesives compared to rosin-based resins and terpene resins, and raw materials are difficult to obtain. There was a manufacturing problem in that cyclopentene, which is difficult to identify, had to be an essential component. Therefore, the present inventors conducted intensive studies to solve the drawbacks of the prior art, and found that when 1,3-pentadiene, diisobutylene, and α-methylstyrene were copolymerized at a specific ratio, they surprisingly The inventors have discovered that the drawbacks can be overcome and have completed the present invention. The main object of the present invention is to provide a method for efficiently producing a novel hydrocarbon resin that can improve initial adhesive strength without significantly impairing holding power and adhesive strength when producing a rubber adhesive. be. These objects of the invention are based on 30 to 80% by weight of 1,
3-pentadiene, 5-40% by weight of diisobutylene, 5-40% by weight of α-methylstyrene, and 0-15
A monomer mixture containing 1,3-butadiene and a diisobutylene to α-methylstyrene weight ratio of 1:3 to 3:1 is added to a diluent and a Friedel-Crafts type catalyst. Cationic polymerization in the presence of 30-85% by weight of 1,3-pentadiene units, 4-32% by weight of diisobutylene units, 5-40% by weight of α-methylstyrene units, and 0% by weight of 1,3-butadiene units. -12% by weight, and the weight ratio of diisobutylene units to α-methylstyrene units is 1:4 to 2:1, with a molecular weight of 500 to
2000, which can be achieved by producing a hydrocarbon resin with a softening point of 60-140°C. The monomer mixture used in the present invention is
30-80% by weight of 1,3-pentadiene, preferably
35-75% by weight, diisobutylene 5-40% by weight, preferably 8-30% by weight, α-methylstyrene 5-40% by weight
40% by weight, preferably 8-30% by weight, and 1,3
- 0 to 15% by weight, preferably 2 to 10% by weight of butadiene. As the content of diisobutylene and α-methylstyrene in the monomer mixture increases, the softening point and melt viscosity of the resulting hydrocarbon resin decrease, and the compatibility with rubber and thermoplastic resin becomes better. If their content becomes too large, the softening point of the resulting hydrocarbon resin will drop too much and the reaction rate will also drop, so the content of 1,3-pentadiene must be at least 30% by weight. Furthermore, in the present invention, among such monomer compositions, the weight ratio of diisobutylene to α-methylstyrene is 1:3 to 3:1, preferably 1:
It is necessary to set the ratio to be 2.5 to 2.5:1, and if it is outside this range, even if both monomers are used together, it will not be possible to obtain the synergistic effect of improving the initial adhesive strength, which is the objective of the present invention. On the other hand, if the 1,3-pentadiene content of the monomer mixture is too high, the polymerization system becomes unstable and gel-like polymers are likely to be formed, and the melt viscosity of the resulting hydrocarbon resin and other heat Since there are also difficulties in compatibility with plastic resins, the content of 1,3-pentadiene needs to be 85% by weight or less. In addition, in the present invention, 1,3-butadiene may be mixed in an amount of 15% by weight or less, preferably 2 to 10% by weight, if desired. Copolymerizing 1,3-butadiene in addition to the three components of 1,3-pentadiene, diisobutylene, and α-methylstyrene provides excellent tack and adhesion when used as a pressure-sensitive adhesive or hot melt adhesive. A hydrocarbon resin is obtained. Furthermore, the monomer mixture used in the present invention may contain other copolymerizable unsaturated hydrocarbons within a range that does not essentially impede the effects of the present invention. For example, in the case of aliphatic monoolefins having 4 to 10 carbon atoms such as butene, pentene, hexene, heptene, etc., up to about 20% by weight may be included in the monomer mixture, but isoprene,
When diolefins such as cyclopentadiene, methylcyclopentadiene, and dicyclopentadiene are present in large amounts in the monomer mixture, the resulting hydrocarbon resin has a high melt viscosity and has difficulty in compatibility with rubber and thermoplastic resins. Therefore, it is preferable to keep their content below 5% by weight in the monomer mixture. In the present invention, such a monomer mixture is cationically polymerized in the presence of a Friedel-Crafts type catalyst and a diluent according to a conventional method. Examples of the catalyst used include aluminum halides, boron halides, tin halides, etc. Among them, aluminum halides, particularly aluminum chloride, are preferred. Further, as the diluent, any of aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons, and halogenated hydrocarbons can be effectively used. However, in general, when aliphatic hydrocarbons such as pentane and hexane are used as polymerization solvents, gel-like polymers that are insoluble in hydrocarbons tend to be formed when the 1,3-pentadiene concentration in the monomer composition is high; , when using halogen-containing solvents such as carbon tetrachloride,
Similarly, a gel-like polymer is easily produced, or a resin with a low softening point is produced. Therefore, in the present invention, it is preferable to use aromatic hydrocarbons as a polymerization solvent, and even when mixed with other solvents, aromatic hydrocarbons should account for at least 50% by weight of the total polymerization solvent. is advantageous. This solvent usually contains 20 to 1000 parts by weight per 100 parts by weight of monomer.
It is used in proportions of 50 to 500 parts by weight, preferably 50 to 500 parts by weight. Polymerization is usually carried out at -20 to 100°C, preferably 0 to 80°C.
The pressure of the reaction system may be at or above atmospheric pressure. The reaction time is also not critical and can generally vary from a few seconds to 12 hours or more. The polymer thus obtained is treated and dried according to conventional methods. The hydrocarbon resin obtained by the present invention has 30 to 85% by weight of 1,3-pentadiene units, preferably 35 to 80% by weight, and 4 to 32% by weight of diisobutylene units, preferably 6 to 21% by weight of diisobutylene units in the polymer chain. Weight%, α-
5 to 40% by weight of methylstyrene units, preferably 8
~30% by weight, and 0 to 12 1,3-butadiene units
% by weight, preferably 2 to 7% by weight, and the weight ratio of diisobutylene units to α-methylstyrene units is 1:4 to 2:1, preferably 1:3.5.
Gardner chromaticity of 6 or less as measured by ASTM D-1544-63T which is ~1.8:1, number average molecular weight of 500-2000, 60-140°C, preferably 65-120°C
It has a softening point specified in JIS K-2531, and is soluble in aliphatic, aromatic, or halogenated hydrocarbon solvents such as pentane, hexane, penzene, xylene, chloroform, and carbon tetrachloride.
It is also a resinous polymer that exhibits low solution viscosity. In addition to these monomer units, this hydrocarbon resin may also contain units of other unsaturated monomers that can be copolymerized, but as their content increases, the performance of the resin decreases. In the case of olefin, it is less than 15% by weight of the total constituent units, and even 10% by weight of the total constituent units.
It is preferably at most 5% by weight of the total units in the case of diolefins. This hydrocarbon resin is well compatible with various synthetic rubbers including natural rubber, synthetic resins such as polyethylene and ethylene-vinyl acetate copolymer, natural resins such as polyterpene and rosin, and various waxes, and is also repellent. It exhibits excellent properties such as water-based properties, adhesion, holding power, peeling power, heat aging resistance, and UV resistance, so it is useful as an adhesive for adhesive tapes when mixed with natural rubber and various synthetic rubbers. It is also useful as a tackifier for imparting tackiness to vulcanized rubber. In particular, when blended with natural rubber, a pressure-sensitive adhesive with excellent initial adhesive strength not only at room temperature but also at low temperature can be obtained. Next, the present invention will be explained in more detail with reference to Examples. Note that parts and percentages used in Examples and Reference Examples are based on weight unless otherwise specified. Example 1 100 parts of benzene and particle size approx. 40 in a glass flask
One part of mesh aluminum chloride was charged and stirred to maintain the system temperature at 40°C. Next, 100 parts of a monomer mixture having the composition shown in Table 1 was gradually added to the above solution continuously over 90 minutes. The temperature of the system rises due to the heat generated by the reaction, so it is cooled down 65
It was kept at ℃. After the addition was completed, the polymerization system was kept at 65°C and stirred for an additional 30 minutes, and then mixed with methanol and 28%
The aluminum chloride was decomposed by adding a mixture of equal volumes of aqueous ammonia. Catalyst particles inactivated by decomposition were removed by filtration, the liquid was transferred to a glass flask, heated while blowing nitrogen to distill off unreacted hydrocarbons and solvent, and then heated to 230°C. raised. Next, saturated steam was blown into the system to remove the low polymer produced by the polymerization reaction and the remaining solvent, and after confirming that almost no oil layer existed in the distillate, steam was blown into the system. The molten residue was taken out and allowed to cool to room temperature, yielding a yellow resinous substance. The average structural unit in the resin is calculated by analyzing the charged monomer composition and the recovered unreacted monomer composition,
Confirmed by infrared absorption spectrum and nuclear magnetic resonance spectrum. For each of the obtained hydrocarbon resins, the softening point (measured by the ring and ball method specified in JIS K-2531),
The number average molecular weight (measured by VPO) and Gardner chromaticity (measured by ASTM D 1544-63T) were measured. The results are shown in Table 2.

【table】

[Table] Example 2 Polymerization was carried out in exactly the same manner as in Example 1 except that a monomer mixture having the composition shown in Table 3 was used. The results are shown in Table 3.

[Table] Reference example In order to evaluate the usefulness of applying the hydrocarbon resins obtained in Examples 1 and 2 to adhesive formulations, natural rubber (pale crepe, Mooney viscosity ML1+
4/100°C60), the following test was conducted. First, 80 parts of hydrocarbon resin and 1 part of antioxidant are mixed with 100 parts of rubber, then toluene is added to make a solution with a solid content concentration of 15%, and this is spread on a 1 mil thick polyester film with a thickness of 25μ. An adhesive tape was prepared by applying the adhesive tape, and its adhesive strength, adhesion strength, and holding power were measured. For comparison, rosin derivatives (hydrogenated rosin glycerin ester softening point 71
℃), make adhesive tape in the same way,
Its physical properties were measured. The results are shown in Table 4. In addition, the adhesive strength is determined by the J.Dow method [Proc.Inst.Rub.
Ind., 1105 (1954)], a 10 cm long adhesive tape was pasted on the slope of a stainless steel plate with a 30 degree inclination, and 30 types of tape from 3/32 inch to 1 inch in diameter were applied from a position 10 cm above the slope. The size of the steel ball is indicated by the size of the largest diameter ball that stops on the adhesive tape when rolled at an initial speed of 0, and the adhesive strength is based on JIS Z-1522. Adhesive tape was pasted on a board with a width of 25 mm x length of 100 mm, and the holding force was measured by peeling it in a 180 degree direction at a speed of 200 mm/min at 25°C. Paste adhesive tape so that an area of 25 mm x 10 mm is in contact with the board and heat it at 40℃.
The time required for the adhesive tape to fall off the stainless steel plate was measured under a load of 1 kg.

[Table] The adhesive obtained by mixing the hydrocarbon resin obtained according to the present invention with natural rubber is compared to the adhesive obtained using a conventionally used rosin derivative (Adhesive 8). It can be seen that the performance is equivalent to or better than that of the previous one. In particular, high initial adhesive strength can be obtained when using a resin copolymerized with 1,3-butadiene (adhesive 4). However, when using a resin that is not copolymerized with either diisobutylene or α-methylstyrene (adhesives 9 to 12)
Even if 1,3-butadiene is copolymerized, the initial adhesion strength is not sufficiently improved.

Claims (1)

[Scope of Claims] 1 1,3-pentadiene 30-80% by weight, diisobutylene 5-40% by weight, α-methylstyrene 5-50% by weight
Cationically polymerizing a monomer mixture containing 40% by weight and 0 to 15% by weight of 1,3-butadiene, and having a weight ratio of diisobutylene to α-methylstyrene of 1:3 to 3:1. The polymer chain is characterized by having (A) 30 to 85% by weight of 1,3-pentadiene units, (B) 4 to 32% by weight of diisobutylene units, and (C) α-
5-40% by weight of methylstyrene units and (D)1,3-
It is composed of 0 to 12% by weight of butadiene units, and the weight ratio of diisobutylene units to α-methylstyrene units is 1:4 to 2:1.The molecular weight is 500 to 2000, and the softening point is 60 to 140°C. A novel method for producing hydrocarbon resin. 2. The method according to claim 1, wherein the polymerization is carried out in the presence of a diluent. 3. The method according to claim 1, wherein the polymerization is carried out in the presence of aluminum halide.