JPH02160886A - Hot-melt adhesive composition - Google Patents

Abstract

PURPOSE:To obtain the title composition excellent in balance among self- adhesiveness, tack, and holding power under conditions from low temperature to high temperature by using a saturated thermoplastic block copolymer elastomer and a specified hydrogenated petroleum resin as constituents. CONSTITUTION:The title composition consists of 100 pts.wt. saturated thermoplastic block copolymer elastomer (e.g. a styrene/hydrogenated polydiene block copolymer); 50-150 pts.wt. substantially saturated hydrogenated 5C petroleum resin which has a number-average molecular weight of 70 to 1,500, a ratio of the weight-average molecular weight to the number-average molecular weight of 1.3 to 2.0, a softening point of 70-130 deg.C, a glass transition point of 55-100 deg.C, a hue of 1 or less, and specified values of initial tack and holding power respectively measured under specified conditions, and in which the principal chain comprises a random linkage consisting mainly of 50-80wt.% 5C diolefin units and 50-20wt.% 5C olefin units and has H2 added so as to substantially saturate these structural units, and 70-90wt.% of said diolefin units form a cyclic structure; and 0-80 pts.wt. softening agent (e.g. polybutene).

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to an excellent hot melt adhesive composition obtained using a hydrogenated C2 petroleum resin. For more details,
The hot melt adhesive composition of the present invention comprises a hydrogenated C2 petroleum resin as a tackifier, a saturated thermoplastic block copolymer elastomer, and, if necessary, a softener.

Conventionally known adhesive compositions are classified into three types: solvent type using an organic solvent, aqueous emulsion type, and hot melt type. Although solvent-based materials have excellent physical properties, they require energy to recover the solvent, and solvent pollution associated with solvent recovery is a problem. Water-based emulsilane type tends to cause curling due to shrinkage during application, and also has problems in the drying process.
There are problems such as water pollution. On the other hand, the hot-melt type is superior in terms of high-speed application, energy saving, and pollution-free properties.

Against this background, there is a demand for the development of hot melt adhesives with excellent performance.

Conventionally, naturally occurring resins such as terpene resins, Q gin resins, and hydrogenated rosin resins have been widely used as tackifiers for hot melt adhesives, and among them, terpene resins have particularly excellent tackiness. It is prized because it has a beneficial effect. However, since it is a natural product, it is unstable in terms of price and supply. Therefore, in recent years, petroleum resins have tended to be used instead of natural products, but they have poor tackifying effects, insufficient heat resistance, and problems with color, odor, etc.

On the other hand, among thermoplastic elastomers, polystyrene-hydrogenated polydiene-polystyrene block copolymer elastomers have recently been recognized as having the best quality, heat resistance, and weather resistance. There is a demand for the development of sex-imparting agents.

(Prior Art) In order to improve the drawbacks of petroleum resins used as tackifiers, attempts have been made to hydrogenate cyclopentadiene resins and aromatic petroleum resins, but in both cases the hue,
Although the odor and heat resistance are improved, the initial adhesion (rolling ball tack), adhesion and holding power are unbalanced and are not sufficient. In other words, when the initial adhesion is increased, the holding and adhesion decreases. (holding force); conversely, when the holding force and adhesive force are increased, the initial adhesive force tends to decrease.

Also, number average molecular weight of 400 to 800, 40 to '70''
Pressure-sensitive adhesive formulations have also been proposed consisting of two components: a hydrogenated petroleum resin with a softening point of C and a glass transition point of less than 45°C and a polystyrene-hydrogenated polystyrene-polystyrene block copolymer elastomer (specially Kaisho 6O-15
477), ! However, this hydrogenated petroleum resin has a low softening point and glass transition point, so it has the advantage of high initial adhesion at low temperatures without the addition of a softener. sex)
has the disadvantage of being low.

(Problem to be Solved) The inventors of the present invention have solved the problem at a wide range of operating temperatures from low to high temperatures.
With the aim of developing a hot-melt adhesive composition with an excellent balance of initial adhesive strength, adhesive strength, and holding power, as well as excellent heat resistance, weather resistance, and color, the present invention was completed after extensive research.

Thus, it is an object of the present invention to provide a hot melt adhesive composition comprising a hydrogenated C7 petroleum resin which is particularly suitable for use as a tackifier, and which adhesive composition has an initial adhesive strength, an adhesive strength It also leads to the production of transparent adhesive tapes with excellent balance in holding power and excellent hue.

(Means for Solving the Problems) That is, the present invention provides -10 as a by-product during thermal decomposition of petroleum.
~10 (a fraction obtained by removing cyclopentadiene from a 1°C fraction, with a total diolefin content of 15
~30% by weight, total olefin content 15-30% by weight
Using a Friedel Krach catalyst, a fraction of
A resin having a main chain of C was produced by polymerizing at 140°C to obtain a resin, and then hydrogenating this resin by a conventional hydrogenation method until it was substantially saturated.

50 to 80% by weight of diolefin units and 50 to 20% by weight of C, olefin units are randomly bonded as main structural units, and the structural units are hydrogenated to substantially saturation, and the above diolefin units 70-91
1% has a cyclized structure with a number average molecular weight of 700~
1500, a weight average molecular weight/number average molecular weight ratio of 1.3 to 2.0, a softening point of 70 to 130°C, a glass transition point of 55 to 100°C, a hue of 1 or less, and polystyrene- Kraton @ G 1657 (manufactured by Shell), which is a hydrogenated polybutadiene-polystyrene type saturated thermoplastic block copolymer elastomer, has an initial adhesive strength (rolling ball tack) of 4 when mixed with 80 parts by weight of 100 parts by weight. ~15 and holding force (load 1kg, 1 degree 7
Substantially saturated hydrogenated C with a temperature of 0.6 mm (5°C)
3 petroleum resin, a saturated thermoplastic bronc copolymer elastomer, and, if necessary, a softener. The hot melt adhesive composition obtained by the present invention has an excellent balance of initial adhesive strength, adhesive strength, and holding power over a wide range of operating temperatures from low to high temperatures, and has excellent heat resistance, weather resistance, and transparency. .

The hydrogen ibis C9 petroleum resin used as a tackifier in the hot melt adhesive composition of the present invention can be produced as follows.

As a raw material, 10 to 10 by-products are produced during thermal decomposition of petroleum.
A Cs fraction from which cyclopentadiene is removed or its content is reduced from the 0°C fraction, or a spent C3 fraction (S-
Cs) is adjusted to have a total diolefin content of 15 to 30% by weight and a total olefin content of 15 to 1% by weight in its fraction by a method such as distillation. If the monoolefin content in the raw material exceeds 30% by weight, the effect of the low molecular weight material (especially retention) will not be sufficient, which is not preferable. If the diolefin content exceeds 30ft1%,
A gel-like substance is likely to form (however, if a solvent is used, it should not exceed 30% by weight based on the raw material containing the solvent), and if it is less than 15% by weight, the yield of the resin will be low and the softening point and A resin with a high glass transition point cannot be obtained, and therefore the tackifying effect (particularly the holding power) of the resin is not sufficient, which is not preferable.

A petroleum resin, which is a raw material for hydrogenated C1 petroleum resin, can be obtained by polymerizing the above raw materials at a polymerization temperature of 50 to 140'C in the presence of a free sol fluorine catalyst. In particular, as a catalyst, a catalyst consisting of a fatty acid ester (A) and an aluminum halide (B) and having a composition of 1.5 to 6.0 moles of (B) per 1 mole of (A) is used, and the amount of the catalyst is controlled. By using 0.5 to 1.5% by weight of aluminum halide to the raw materials and polymerizing at a temperature of 70 to 140°C, a resin with a sharp molecular weight distribution and a high degree of cyclization in the diene polymer portion can be obtained. Hydrogenation is preferable because it yields a hydrogenated C2 petroleum resin with a high softening point and glass transition point, a sharp molecular weight distribution, and a high tackifying effect.

Since polymerization is usually an exothermic reaction, -g is carried out in the presence of a solvent for the purpose of controlling the reaction or preventing the formation of gel. However, when sc and g fractions are used, the reaction can be sufficiently controlled without adding a new solvent, and no gel is formed, so that the polymerization can proceed even without a solvent.

As a solvent during polymerization, aliphatic hydrocarbons, aromatic hydrocarbons, alicyclic hydrocarbons, halogenated hydrocarbons, etc. can be used alone or in combination, and aromatic hydrocarbons are preferably used.

The hydrogenated CS petroleum resin can be obtained by hydrogenating the petroleum resin produced under the above conditions, and the hydrogenation reaction may be carried out according to a conventional method. For example, by dissolving petroleum resin in a hydrocarbon solvent such as hexane, heptane, octane, cyclohexane, benzene, toluene, xylene, etc., or by melting the resin as it is, nickel, palladium, platinum, cobalt, etc.
Hydrogenation may be carried out in the presence of a metal or oxide catalyst such as ruthenium or rhodium at a hydrogen pressure of normal pressure to 350 kg/cm. The resin thus obtained is substantially completely hydrogenated, with C in the main chain.
, 50 to 80% by weight of hydrogenated diolefin units,
Contains 50-20% by weight of C, olefin hydrogenated units, number average molecular weight 700-1500, softening point 70°C-
130'c, a glass transition point of 55°c to too''c, and a hue of 1 or less.

If the number average molecular weight is 700 or less, the softening point is 70'C or less, and the glass transition point is 55°C or less, the holding power at high temperatures will decrease, which is undesirable.On the contrary, if the average molecular weight is 1500 or more and the softening point is 130 C or higher and the glass transition point is 100 C or higher, which is not preferable because the initial adhesive strength (especially at low temperatures) decreases.

Here, the number average molecular weight is G
The glass transition point was determined by PC, the softening point was determined by TBA method, and the softening point was determined by J.
The values were measured according to IS K 2531-60 (ring and ball method), and the hue was measured according to ASTM D-154-58. Hydrogenated C2 thus obtained
When petroleum resin is mixed with 80 parts by weight of Clayre 401657 saturated thermoplastic bronc copolymer elastomer 10 (1 part by weight), rolling tanks 4 to 15 and holding power (weight 1 kg, 1 degree 75°C, 4 degrees 50 χ )0~0.6m
A hot melt adhesive composition having physical properties of m is provided.

Here, the ball tank number (initial adhesive strength) is J
The retention force was measured according to the IS Z-0237-1980 method and the JIS Z-0237-19130 method. However, the load is 1 kg, the temperature is 75°C, and the humidity is 50°C.
It was done in %.

An additional feature of the above hydrogenated C1 petroleum resin is that it has a high proportion of cyclized structures in the resin, which is due to the high diene/monoolefin ratio in the Cs fraction, which is the polymerization raw material. , despite the large number of diene units in the polymer, the glass transition temperature (Tg) of the hydrogenated Cs petroleum resin obtained by hydrogenation treatment is not significantly different from that of the resin before hydrogenation, i.e., 10'C. This is shown below. The fact that there is little change in Tg due to hydrogenation despite the large number of diene units means that the proportion of single-engineered double bonds in the polymer before hydrogenation is small, and a considerable proportion of diene units containing this This is one evidence that the moiety is cyclized.

According to instrumental analysis, hydrogenated C1 petroleum resin is
It is characterized by having a cyclized structure of 5 to 72% by weight, which is about 70 to 9% of the hydrogenated diene unit.
It shows that 11% is cyclized.

Another characteristic is that the molecular weight distribution is sharp, and M w /M n is in the range of 1.3 to 2.0.

Furthermore, the adhesive strength (JIS Z-0237198
0) is as high as 450-700g/25m-, and another feature is that the difference between the softening point and Tg is large, that is, 25-40°C1.

The hot-melt adhesive composition of the present invention is obtained by using the hydrogenated resin obtained by the above method as a tackifier, blending therein with a thermoplastic block copolymer elastomer, and optionally adding a softening agent. or an antioxidant may be added.

As a saturated thermoplastic block copolymer elastomer,
Preferably, polystyrene-polybutadiene-polystyrene, polystyrene-polyisoprene polystyrene in which polybutadiene or polyisoprene is hydrogenated is used. M! Waju thermoplastic block copolymer elastomer has excellent heat resistance, weather resistance, and color. The number average molecular weight of this saturated thermoplastic block copolymer elastomer is from 20,000 to 500,000, preferably from 50,000 to 200,000.

As the elastomer in the adhesive composition, an elastomer with a high molecular weight and a low glass transition point is generally used. It's helpful. On the other hand, as a tackifying agent, a relatively low molecular weight resin is generally used, and this is thought to fill the gaps between the macromolecular elastomers and improve compatibility with the material to be bonded. Therefore, since the elastomer has a high molecular weight side, the tackifier does not need to contain too many high molecular weight components, and containing too many low molecular weight components will weaken the adhesive strength, so the tackifier should have a molecular weight within an appropriate range. It is desirable to have a narrow molecular weight distribution.

If the adhesive composition obtained by blending hydrogenated C1 petroleum resin and saturated thermoplastic block copolymer elastomer is too hard or dry, a softener may be added as desired. be able to.

As the softener, liquid resins such as polybutene and polybutadiene, naphthenic and paraffinic process oils, etc. can be used, but polybutene and purified process oils are preferred from the viewpoint of heat resistance and weather resistance.

The blending ratio of the hot melt adhesive is not particularly strictly regulated and can be used in any ratio, but from the viewpoint of performance and processing, it is recommended to mix 50 to 150 parts by weight of the hydrogenated resin to 10 parts by weight of the thermoplastic elastomer. Preferably 70 to 120 parts by weight, softener 0 to 80 parts by weight, preferably 10 to 541 parts by weight.
It is better to choose the part.

The hot melt adhesive composition obtained as described above has an excellent balance of tank strength, adhesive strength, and holding power in a wide range of operating temperatures from low to high temperatures, and also has excellent heat resistance, weather resistance, and transparency. Are better.

(Example) Examples will be shown below to further clarify the content of the present invention, but the present invention is not limited by these examples.

Reference Example 1 (Method for producing raw petroleum resin) A catalyst was prepared by heating and mixing 3.0 g (23.1 ssol) of aluminum chloride and 0.99 g (13.4 m5 ol) of methyl acetate in advance. The catalyst was placed in an 11 glass autoclave equipped with a stirrer, a thermometer and a 7-meter addition funnel, and then 30 at! of benzene was added.
diluted with While maintaining this autoclave at 90°C, the boiling points of -10 to 100 of the thermal decomposition products of petroleum fractions were
Fraction 300111 having the composition in Table 1 obtained from the fraction at °C
! Approximately 30 powders of grains were added dropwise from the dropping funnel. After completing the bond, react with stirring at 90℃ for 1 hour, and then add alkaline water. The catalyst was decomposed using liquid 8, and the catalyst was removed by repeated washing with water. Next, the polymerization liquid was taken out, unreacted raw material oil and benzene as a solvent were distilled off under normal pressure, and low polymers were further distilled off under reduced pressure. The obtained petroleum resin weighed 58 g and did not contain gel. Further, the diolefin component ratio in the resin was 61.5 wt%, and its physical properties were as shown in Table 2.

Table 1 Composition of raw materials The total amount of monoolefins in the raw materials is 23.1! I%, the total diene is 23.7% by weight, and the diene/monoolefin weight ratio is about 1.

Table 2 Physical Properties of Petroleum Resin Reference Example 2 (Production method of raw petroleum resin) A catalyst was prepared by heating and mixing 3.3 g (25,4 ssol) of aluminum chloride and 1.09 g (14,7 ssol) of methyl acetate in advance. The catalyst was placed in a glass autoclave equipped with a stirrer, a thermometer and a monomer addition funnel, after which it was diluted with 30 d of benzene. While maintaining this autoclave at 80"C, heat decomposition products of petroleum fractions with boiling points of -10 to 100"
300 d of fraction having the composition shown in Table 3 obtained from the fraction at ℃ was added dropwise from the dropping funnel over a period of about 30 minutes.
After reacting at 90° C. for 1 hour with stirring, the catalyst was decomposed with an aqueous alkali solution and further washed with water repeatedly to remove the catalyst. Next, the polymerization liquid was taken out, unreacted raw material oil and benzene as a solvent were distilled off under normal pressure, and low polymers were further distilled off under reduced pressure.

The obtained petroleum resin weighed 55 g and did not contain gel. In addition, the diolefin component ratio in the resin is 67.0
wt%, and its physical properties are as shown in Table 4.

Composition of surface raw material The total monoolefin in the raw material is 21.4% by weight, the total diene is 21.6% by weight, and the diene/monoolefin weight ratio is about 1.

Table 4 Physical Properties of Petroleum Resin When this resin was analyzed by infrared absorption spectrum and NMR spectrum, no absorption based on double bonds was observed. The physical properties of this resin are shown in Table 5.

Table 5 Physical Properties of Hydrogenated Resin Reference Example 3 (Hydrogenation of Petroleum Resin) 250 g of the same resin obtained in Reference Example 1 and 250 # of cyclohexane were placed in a 11 stainless steel autoclave. and Nokel 50% on nickel-diatomaceous earth catalyst) 10g
After adding hydrogen, the inside was replaced with hydrogen, and the hydrogen pressure was 60 kg/cm.
'', hydrogenation was carried out at a temperature of 200'C for 6 hours.

After the reaction was completed, the contents were taken out, the catalyst was removed by φ filtration, and cyclohexane was distilled off first at normal pressure and then under reduced pressure to obtain about 245 g of hydrogenated resin. Reference Example 4 (Hydrogenation of Petroleum Resin) ) In a stainless steel autoclave with Il, 250 g of the same resin obtained in Example 2, cyclohexane 250 #2 and 50% Nokel on nickel-diatomaceous earth catalyst) log
After adding hydrogen, the inside was replaced with hydrogen, and the hydrogen pressure was 60 kg/c+
++', hydrogenation was carried out at a temperature of 200° C. for 6 hours.

After the reaction was completed, the contents were taken out, the catalyst was removed by filtration, and cyclohexane was distilled off first at normal pressure and then under reduced pressure to obtain about 245 g of hydrogenated resin. When this resin was analyzed by infrared absorption spectrum and NMR spectrum, no absorption based on -multiple bonds was observed. The physical properties of this resin are shown in Table 6.

Table 6 Physical properties of hydrogenated resin Example 1 Saturated thermoplastic block copolymer "Krayton 0G165"
An adhesive was prepared by uniformly mixing 100 parts of 7J with 60 parts of the resin obtained in Reference Example 4 and 220 parts of toluene as a solvent.

This adhesive was applied onto a polyester film with a thickness of 25 μm, and then dried to prepare an adhesive film with a thickness of 50 μm.

The resulting adhesive had an initial adhesive strength (ball seed) of 14, an adhesive strength of 155 g/25 mm, and a holding strength of 0.3 m+++.

Initial adhesive strength, adhesive strength and holding strength are JIS Z023
7-1980. In addition, the holding force is a load of 1 kg.

The distance that the adhesive tape shifts during 2 hours was measured under conditions of a temperature of 75°C and a humidity of 50%, and the initial adhesive strength was measured at 23"C.

Example 2 Saturated thermoplastic block copolymer “Krayton 0G165”
An adhesive was prepared by uniformly mixing 100 parts of 7J with 100 parts of the resin obtained in Reference Example 4 and 220 parts of toluene as a solvent.

This adhesive was applied onto a polyester film with a thickness of 25 μm, and then dried to prepare an adhesive film with a thickness of 50 μm.

The obtained adhesive had an initial adhesive force (ball Nα) of 5, an adhesive force of 745 g/25 m5, and a holding force of 0.6 mm.

Examples 3 to 4 and Comparative Examples 1 to 2 To 100 parts of Kraton 8G1657, the resins obtained in Reference Examples 3 and 4, and commercially available hydrogenated cyclopentadiene resins and hydrogenated aromatic petroleum resins as comparative examples were added, respectively. 80 parts and 22 parts of toluene as solvent
A pressure-sensitive adhesive film was prepared in the same manner as in Example 1 using 0 parts.

Table 7 shows the test results of the obtained adhesive.

Examples 5-6 and Comparative Examples 3-4 To 100 parts of Kraton 801657, the resins obtained in Reference Examples 3 and 4 and the commercially available hydrogenated cyclopentadiene resin used in Comparative Example 1 and the comparison An adhesive film was prepared in the same manner as in Example 1 using 100 parts of each of the commercially available hydrogenated aromatic petroleum resins used in Example 2, 25 parts of polybutene as a softener, and 220 parts of toluene as a solvent.

Table 8 shows the test results of the obtained adhesive.

As can be seen from this experimental result, the hydrogenated C1 petroleum resin of the present invention has an excellent balance of initial adhesive strength, adhesive strength, and holding power compared to commercially available hydrogenated petroleum resins, and in particular, despite its high initial adhesive strength, It is clear that the holding power is high.

(Effect of the invention) The hot melt adhesive composition of the present invention has a specific hydrogenated C
2 Petroleum resin is blended into a saturated thermoplastic block copolymer elastomer as a tackifier, and if necessary, a softener is added to improve tank adhesion and retention in a wide operating temperature range from low to high temperatures. It has an excellent power balance, and also has excellent heat resistance, weather resistance, and transparency.

Claims (4)

[Claims] (1) (A) 100 parts by weight of saturated thermoplastic block copolymer elastomer, (B) main chain consisting of 50-80% by weight of C_5 diolefin units and 50-20% by weight of C_5 olefin units, randomly bonded as main structural units. and the structural unit is hydrogenated to substantially saturation,
In addition, 70 to 90% by weight of the diolefin units have a cyclized structure, a number average molecular weight of 700 to 1,500, and a weight average molecular weight/number average molecular weight ratio of 1.3 to 2.
0, softening point 70-130℃, glass transition point 55
~100°C, with a hue of 1 or less, and for 100 parts by weight of a polystyrene-hydrogenated polybutadiene-polystyrene type saturated thermoplastic block copolymer elastomer,
Initial adhesive strength (rolling ball tack) when mixed with 80 parts by weight
4 to 15 and holding force (load 1 kg, temperature 75°C) is 0
．． A hot melt adhesive composition comprising 50 to 150 parts by weight of a substantially saturated hydrogenated C_5 petroleum resin having a diameter of 6 mm and (C) 0 to 80 parts by weight of a softener. (2) The hot melt adhesive composition according to claim 1, wherein the saturated thermoplastic block copolymer elastomer is a block copolymer of styrene and hydrogenated polydiene. (3) The hot melt adhesive composition according to claim 1 or 2, wherein the hydrogenated petroleum resin is 50 to 120 parts by weight based on 100 parts by weight of the saturated thermoplastic block copolymer elastomer. . (4) The hot melt adhesive according to any one of claims 1 to 3, wherein the softener is 10 to 50 parts by weight based on 100 parts by weight of the saturated thermoplastic block copolymer elastomer. Composition.