JP2701268B2 - Block copolymer composition - Google Patents

Description

The present invention relates to a novel aromatic vinyl-conjugated diene block copolymer composition, particularly an aromatic compound having a specific structure useful for a pressure-sensitive adhesive composition and the like. The present invention relates to a block copolymer composition comprising a vinyl block and a conjugated diene block. b. Conventional technology Generally, the adhesive is an adhesive tape such as croft tape,
It is used for forming an adhesive layer such as a label or other adhesive sheet. As such an adhesive, an adhesive which has an appropriate fluidity when melted by heat and which can be applied to a substrate as it is without using an organic solvent to form an adhesive layer is desired. c. Problems to be Solved by the Invention Conventionally, as such a hot-melt adhesive, for example, those described in Japanese Patent Publication No. 50-56426 and Japanese Patent Application Laid-Open No. 54-33536 are known. However, these conventional pressure-sensitive adhesives do not simultaneously have all of the important properties required for the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet, such as tack and holding power. d. Means for Solving the Problems The present invention has made intensive studies in view of the above problems, and as a result, a block copolymer having a specific structure is converted with a polyfunctional tin-based coupling agent and a non-tin-based coupling agent. It was completed by finding that a hot-melt type adhesive excellent in various properties could be obtained by using the coupled product, and when applied to an adhesive tape, tack, adhesive strength and retention An object of the present invention is to provide a block copolymer composition useful as a hot-melt type pressure-sensitive adhesive having excellent properties in all of its strengths. That is, the present invention is, (1) (A) the general formula [(A-B ₁₎ l _1] m-Y ₁ (In the formula, A an aromatic vinyl polymer block having a molecular weight of 10,000 to 30,000, B ₁ is A conjugated diene polymer block,
l ₁ is an integer of 1 to 3, m is an integer from 2 to 4, Y ₁ represents a residue of a coupling agent other than tin coupling agent. Block copolymer 20 to 60 wt%, represented by), (B) the general formula [(A-B ₂₎ l _2] n-Y ₂ (wherein, A represents an aromatic vinyl molecular weight 10,000 to 30,000 heavy Coalescing block, B ₂ is a conjugated diene polymer block,
l ₂ represents an integer of 1 to 3, m represents an integer of 2 to 4, and Y ₁ represents a residue of a tin-based coupling agent. Block copolymer 50 to 10 wt%, represented by), and (C) the general formula _{(A-B 3) l 3} ( In the formula, A an aromatic vinyl polymer block having a molecular weight of 10,000 to 30,000, B ₃ Is a conjugated diene polymer block;
The component (B) of the conjugated diene polymer block B ₂ of molecular weight from 1.2 times or more greater conjugated diene polymer block, l ₃ is an integer of 1-3. The present invention provides a block copolymer composition comprising 10 to 50% by weight of a block copolymer represented by the following formula: e. Specific Description of the Invention <Constituent Components> The constituent components constituting the block copolymer composition of the present invention include the following. Aromatic vinyl compound As the aromatic vinyl compound used in the present invention, styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, o-methylstyrene, p-te
rt-butylstyrene, dimethylstyrene, vinylnaphthalene and the like can be used. Of these, styrene is preferred. Conjugated diene compound As the conjugated diene compound, butadiene, isoprene, piperylene and the like can be used. Of these, isoprene is preferred. Coupling agents other than tin-based coupling agents Examples of the coupling agent other than the tin-based coupling agent used in the present invention include divinylbenzene, divinyl aromatic compounds such as divinylnaphthalene, dichloroethane, dibromoethane, methylene chloride, and dibromomethane. , Dichloropropane, dihalogenated alkanes such as dibromopropane, chloroform, trichloroethane,
Trihalogenated alkanes such as trichloropropane and tribromopropane, benzoates, silicon tetrachloride,
Dimethyldichlorosilicon, silicon halide compounds such as tetrabromosilicon, CO, 2-chloropropene, 1-chloro-1,3-butadiene, and the like can be used. Among these, silicon halide is preferable in terms of coupling efficiency. Compounds are preferred. As the silicon halide compound, a hydrocarbon group represented by the general formula RpSiXq (where R is a hydrogen atom or CnH _{2n + 1} (n = 1 to 20 integers, preferably 1 to 8 integers), X is Cl or A halogen represented by Br or the like, p is an integer of 0 to 2, and q is an integer of 2 to 4, preferably p = q = 2.
Monomethyldichlorosilane, dimethyldichlorosilane,
Monoethyldichlorosilane, diethyldichlorosilane,
Monobutyldichlorosilane, dibutyldichlorosilane,
Monohexyldichlorosilane, dihexyldichlorosilane, dibromosilane, monomethyldibromosilane, dimethyldibromosilane and the like are used. Tin Coupling Agent As a typical example of the tin coupling agent used in the present invention, a tin halide compound may be mentioned, and the following general formula RaSnXb (where R is a hydrogen atom or CnH _{2n + 1} (n = 1 to 1) 20, preferably an integer of 1 to 8), and X is
A halogen such as Cl or Br, a is an integer of 0 to 2 and b is an integer of 2 to 4; Are preferred, for example, dichlorotin,
Monomethyldichlorotin, dimethyldichlorotin, monoethyldichlorotin, diethyldichlorotin, methyltrichlorotin, monobutyldichlorotin, dibutyldibromotin, monohexyldichlorotin, tetrachlorotin and the like are used. Hydrocarbon Solvent As the hydrocarbon solvent used for producing the block copolymer of the present invention, for example, cyclopentane, cyclohexane, benzene, ethylbenzene, xylene and a mixture thereof with pentane, hexane, heptane, butane and the like are used. Organolithium compound As the organolithium compound used as the polymerization initiator, for example, n-butyllithium, sec-butyllithium, tert-butyllithium, n-hexyllithium, is
There are o-hexyllithium, phenyllithium, naphthyllithium and the like, which are used in an amount of 0.01 to 1.0 part by weight per 100 parts by weight of the monomer. <Production Method> The block copolymer composition of the present invention can be obtained by producing each block copolymer using the above constituent components and an organic lithium compound in a hydrocarbon solvent as a polymerization initiator. [Component (A)] Step A (a) The aromatic vinyl compound is polymerized until the molecular weight of the aromatic vinyl compound polymer reaches 10,000 to 30,000. When the molecular weight of the aromatic vinyl compound is less than 10,000, when it is used as an adhesive, the holding power is poor, and when it exceeds 30,000, tack becomes worse. (B) Then, a conjugated diene compound is added and polymerized, and the polymer of the conjugated diene compound has a molecular weight of 20,000 to 200,000,
Preferably, the polymerization is carried out until 50,000 to 150,000. If the molecular weight of the conjugated diene is less than 20,000, the tack is poor, and if it is 200,000 or more, the holding power is poor. Step B After repeating (a) and (b) in Step A for 0 to 2 times, preferably 0 times (that is, after Step A), a silicon-based compound coupling agent is added, and the total aroma generated in Step A is added. The silicon halide compound is coupled to an aromatic vinyl-conjugated diene block copolymer. [Component (B)] Step A (a) The aromatic vinyl compound is polymerized until the molecular weight of the polymer of the aromatic vinyl compound reaches 10,000 to 30,000. When the molecular weight of the aromatic vinyl compound is less than 10,000, when it is used as an adhesive, the holding power is poor, and when it exceeds 30,000, tack becomes worse. (B) A conjugated diene compound is further added and polymerized until the molecular weight of the polymer of the conjugated diene compound reaches 20,000 to 200,000, preferably 50,000 to 150,000. If the molecular weight of the conjugated diene is less than 20,000, the tack is poor, and if it is 200,000 or more, the holding power is poor. Step B After repeating Steps (a) and (b) in Step A for 0 to 2 times, preferably 0 times (that is, after Step A), a tin-based coupling agent is added, and the total amount formed in Step A is increased. The tin-based coupling agent is coupled to the aromatic vinyl-conjugated diene block copolymer. [Component (C)] (a) The aromatic vinyl compound is polymerized and polymerized until the molecular weight of the aromatic vinyl compound polymer becomes 10,000 to 30,000. When the molecular weight of the aromatic vinyl compound is less than 10,000, when it is used as an adhesive, the holding power is poor, and when it exceeds 30,000, tack becomes worse. (B) A conjugated diene compound is further added, and polymerization is carried out until the molecular weight of the polymer of the conjugated diene compound reaches 30,000 to 300,000, preferably 50,000 to 250,000. If the molecular weight of the conjugated diene is less than 30,000, the tack is poor and 300,000
If it exceeds, the holding power is poor. Further, the above (a) and (b) are repeated 0 to 2 times, preferably 0 times. The reaction conditions in each of these steps are carried out under the usual polymerization conditions and coupling conditions, and can be produced by either an isothermal polymerization method or an adiabatic polymerization method. The polymerization temperature range is generally 30 to 120 ° C., preferably 50 to 8 ° C.
At 0 ° C, the coupling temperature is generally between 30 and 120 ° C. The composition of the present invention is obtained by combining the above components. The composition of the present invention can also be obtained by partially coupling the above-mentioned component (A), further partially coupling with a tin-based coupling agent, and subsequently adding conjugated diene to proceed with polymerization. be able to. <Composition> The block copolymer composition produced as described above has (1) (A) a general formula [(A-B ₁ ) l ₁ ] m-Y ₁ (where A has a molecular weight of 10,000). ~ 30,000, preferably 15,0
00 to 25,000 aromatic vinyl polymer blocks, B ₁ is a conjugated diene polymer block, and l ₁ is 1 to 3, preferably 1
And m is an integer of 2 to 4, preferably 2, and Y ₁ represents a residue of a coupling agent other than a tin-based coupling agent. 20) to 60% by weight of the block copolymer represented by
30 to 50% by weight, if less than 20% by weight the holding power is poor,
If it exceeds 60% by weight, tack and adhesive strength are poor. (B) the general formula [(A-B ₂₎ l _2] in n-Y ₂ (wherein, A is the molecular weight of 10,000 to 30,000, preferably 15,0
00 to 25,000 aromatic vinyl polymer blocks, B ₂ is a conjugated diene polymer block, and l ₂ is 1 to 3, preferably 1
, Preferably an integer of 2 to 4, preferably 2, Y ₂ represents a residue of a tin-based coupling agent. 50 to 10% by weight of the block copolymer represented by
When it is 40 to 20% by weight, if it is less than 10% by weight, the adhesive strength is inferior, and when it exceeds 50% by weight, the tack and the holding power are inferior. (C) the general formula _{(A-B 3) l 3} ( In the formula, A molecular weight of 10,000 to 30,000, preferably 15,0
Aromatic vinyl polymer block 00~25,000, B ₃ is a conjugated diene polymer block, said component (B) of the conjugated diene polymer block B ₂ of molecular weight from 1.2 times or more greater conjugated diene polymer block, l ₃ Represents an integer of 1 to 3, preferably 1. 10) to 50% by weight of the block copolymer represented by
When the content is less than 10% by weight, the tack and the adhesion are inferior, and when it exceeds 50% by weight, the adhesion and the blocking resistance of the polymer are inferior. In the block copolymer, the molecular weight of B ₃ is 1.2 times or more B _2, preferably 1.2 to 15 times, more preferably
The ratio is 1.3 to 10 times, particularly preferably 1.5 to 8 times. If it is less than 1.2 times, the balance between tack and holding power is poor, and a good pressure-sensitive adhesive cannot be obtained. In addition, B _{1 of the} component (A)
The ratio of the molecular weight / (B) of the components of B ₂ separation amount, preferably 1 ± 0.4, more preferably 1 ± 0.2, particularly preferably 1
± 0.1. (A) The block copolymer composition of the present invention comprising (B) and (C) contains 5 to 40% by weight of a vinyl aromatic compound component,
It is preferably contained in an amount of 10 to 30% by weight, more preferably 10 to 20% by weight. When the aromatic vinyl compound is used in a mixture with a tackifier component of less than 5% by weight, the holding power becomes poor, If it exceeds 40 parts by weight, the touch becomes inferior. When a tackifier component is mixed with the block copolymer composition and used, the tackiness and the holding power are remarkably selected. <Use> When the block copolymer composition of the present invention is used as a pressure-sensitive adhesive, a tackifier is blended. Examples of the tackifier include rosin resins, polyterpene resins, synthetic polyterpene resins, alicyclic hydrocarbon resins, cumarone resins, phenol resins, terpene-phenol resins, aromatic hydrocarbon resins, and fatty acids. A group hydrocarbon resin is used. Of these, rosin resins, polyterpene resins, and aliphatic hydrocarbon resins are particularly preferred. These tackifiers can be used alone or in combination of two or more. The compounding amount of the tackifier is
Generally 2 to 100 parts by weight of the block copolymer composition
0 to 200 parts by weight, preferably 50 to 150 parts by weight. If the compounding amount of the tackifier is out of the above range, there is a possibility that appropriate tack and holding power may not be sufficient. These compounds may further contain a softening agent, such as a naphthenic, paraffinic,
Aroma-based process oils and the like can be used alone or in combination of two or more. The amount of the softener is from 0 to 200 parts by weight, preferably from 20 to 120 parts by weight, based on 100 parts by weight of the copolymer. If the amount of the softening agent exceeds 200 parts by weight, the softening agent oozes out onto the adhesive surface with the lapse of time, which has an undesirable effect. When the composition of the present invention is used for an adhesive, it is preferable to add an organic acid. As the organic acid, stearic acid, oleic acid, aliphatic monocarboxylic acids such as palmitic acid, maleic acid,
Aliphatic dicarboxylic acids such as fumaric acid, aromatic monocarboxylic acids such as benzoic acid, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, abietic acid, neoabietic acid, dihydroabietic acid, tetrahydroabietic acid, α Resin acids such as -pimaric acid, iso-α-pimaric acid, dehydroabietic acid, levopimaric acid and the like can be used alone or as a mixture of two or more. The amount of the organic acid is the same as that of the block copolymer composition 10.
20 parts by weight or less relative to 0 parts by weight, preferably 0.01 to 20 parts by weight, more preferably 0.1 to 15 parts by weight, more preferably
0.2 to 10 parts by weight are used. When the compounding amount of the organic acid is within the above range, an adhesive having an excellent balance between the initial adhesive strength and the adhesive holding power can be obtained. In addition to the above, if necessary, antioxidants, stabilizers such as ultraviolet absorbers, calcium carbonate, talc, clay,
An inorganic filler such as titanium oxide, silica, magnesium carbonate, and carbon black, a coloring agent, and the like may be added. Further, the block copolymer composition of the present invention and an aromatic vinyl-conjugated diene block copolymer other than the present invention (for example, KRATON D1107 and KRATON D1117 manufactured by Shell Chemical, QUINTAC 3420 and QUINTAC 3420 manufactured by Zeon Corporation) QUINTA
C3435, KRATON KX-65 manufactured by Shell Chemical Co., Ltd., Tufprene A manufactured by Asahi Kasei Corporation), natural rubber, rubber such as SBR, IR and EPDM, and plastics such as PE, PP and EVA may be mixed. Each component of the above pressure-sensitive adhesive composition is a general tank-type mixer,
In a closed kneader, etc., under heating at 120 to 180 ° C,
If necessary, they are mixed in a nitrogen gas atmosphere. Since the pressure-sensitive adhesive composition thus obtained forms a pressure-sensitive adhesive layer by being applied to a substrate, various pressure-sensitive adhesive tapes, labels, various types of lightweight plastic molded product fixing back paste, carpet fixing back paste, etc. And as an adhesive layer forming material for adhesive tapes and labels used in frozen foods and cold regions. In addition, the use of the block copolymer of the present invention covers a wide range, but examples thereof include footwear, injection molded products such as containers, toys, blow molded products such as household goods, packing, sheets, plates and the like. It can be suitably used for compression molded articles and the like. Further, the block copolymer of the present invention is mixed with other rubbers such as SBR and NBR, plastics such as polystyrene, and the like, and used for those whose physical properties are modified. For example, it is used as a crepe sponge for rubber applications and as an improver for impact resistance of general-purpose polystyrene for plastic applications. Further, the block copolymer of the present invention is mixed with asphalt and used to improve the cold resistance of asphalt. f. Examples The present invention will be described in detail below with reference to examples of the present invention, but the present invention is not limited thereto unless it exceeds the gist of the present invention. Various measurements were made according to the following methods. Tack: PSTC # 6 rolling ball tack method Roll a steel ball having a diameter of 7/16 "on an inclined plate with an angle of 21.5 ° and find the distance at which it stops on a tape sample stuck on a horizontal plate. When measured at an ambient temperature of 1, the running distance was 15 cm.Heat adhesion: JIS-Z-1522 180 ° C peeling test An adhesive tape sample was cut into a 10 mm width, adhered to a SUS304 plate, and peeled at a tensile speed of 300 mm / min. Holding force: JIS-Z-1524 Cut the adhesive tape sample into 15mm width, adhere to SUS304 plate with a fixed area of 15mm x 25mm, suspend 1.2kg load on one end of the tape, peel off the adhesive surface and drop time However, the ambient temperature was 40 ° C. Blocking resistance: 50 g of a crumb sample coated with 0.5 phr of talc was placed in a 100 cc beaker, and the crumb sample was added.
It is left at 50 ° C. for 3 days under a pressure of 0.1 kg / cm ² . Then take out the crumb sample, drop it from a height of 1m,
The blocking resistance was determined by the following equation. Blocking resistance = {50− (weight of block of three or more crumbs)} / 50 Amount of bound styrene: determined by an infrared method. Molecular weight: determined from the peak value of GPC. Example 1 Method for Producing (AB ₁ ) ₂ -Y ₁ Type Block Copolymer Cyclohexane / n-pentane = 9/1 mixed solution (1600 g) was placed in a washed and dried stirrer and jacketed autoclave under a nitrogen atmosphere. And 0.12 g of tetrahydrofuran, and then the internal temperature was adjusted to 60 ° C. Next, after adding a hexane solution containing 0.5 g of n-butyllithium, 97 g of styrene was further added and polymerization was carried out for 60 minutes. The polymerization conversion of styrene was 100%. Next, 303 g of isoprene was added and polymerization was carried out for 60 minutes. The polymerization conversion of isoprene was 100%. Next, a cyclohexane solution containing 0.44 g of monomethyldichlorosilane was converted and a coupling reaction was performed for 20 minutes. During the polymerization, the temperature was constantly adjusted to 70 ° C. After completion of the polymerization, 2,6-di-tert-butyl- was added to the polymer solution.
After adding p-cresol, cyclohexane / n-pentane was removed by heating to obtain a block copolymer. Di instead of _{(A-B 2) 2 -Y} 2 type block copolymer production methods monomethyl dichlorosilane 0.44 g-n-
(A) except that 1.26 g of butyl-dichlorotin was used.
-B ₁₎ to obtain a copolymer in the same manner as ₂ -Y ₁ type block copolymer. Production method of (A-B ₃ ) type block copolymer After charging a mixed solution of cyclohexane / n-pentane = 9/1 and 0.12 g of tetrahydrofuran into a washed and dried autoclave equipped with a stirrer and a jacket under a nitrogen atmosphere. The internal temperature was brought to 60 ° C. Next, after adding a hexane solution containing 0.5 g of n-butyllithium, 36.4 g of styrene was further added and polymerization was carried out for 60 minutes. The polymerization conversion of styrene was 100%. Next, 363.6 g of isoprene was added and polymerization was carried out for 60 minutes. The polymerization addition rate of isoprene was 100%. During the polymerization, the temperature was always adjusted to 70 ° C. After completion of the polymerization, 2,6-di-tert-butyl- was added to the polymer solution.
After adding p-cresol, cyclohexane / n-pentane was removed by heating to obtain a block copolymer. The thus obtained _{(A-B 1) 2 -Y} 1 type block copolymer _{(A-B 2) 2 -Y} 2 type block copolymer and (A-B ₃₎ block copolymer Were blended in the proportions shown in Table 2 to obtain a block copolymer composition. Table 2 shows the evaluation results. The composition used in Table 2 is as follows. Block copolymer composition / aliphatic petroleum resin (1) /
Naphthenic process oil (2) / anti-aging agent (3) =
100/100/20/2 (1) ESCOLETS 1310 manufactured by Exxon Chemical (2) SHELL FLEX371 manufactured by Shell Kosan (3) Irganox 1010 manufactured by Ciba Geigy Examples 2 to 7, Comparative Examples 1 to 6 Polymerization was carried out in the same manner as in Example 1 except that a predetermined amount of styrene, isoprene, a silicon-based coupling agent and a tin-based coupling agent were used. Table 2 shows the evaluation results. Comparative Example 1 The component (A) is less than the range of the present invention, and the holding power is inferior. Comparative Example 2 The component (A) exceeds the range of the present invention, and the tack is inferior. Comparative Example 3 The component (B) was less than the range of the present invention, and the blocking resistance was poor. Comparative Example 4 The component (C) was less than the range of the present invention, and both tackiness and adhesive strength were poor. Comparative Example 5 The molecular weight of the block of the styrene polymer as the component (A) is less than the range of the present invention, and the adhesive strength, holding power and blocking resistance are inferior. Comparative Example 6 The molecular weight of the block of the styrene polymer as the component (A) exceeds the range of the present invention, and the tack is poor. Comparative Example 7 The ratio of B _{3 of} component (C) / B ₂ of component (B) was 1.0, which was less than the range of the present invention, and both tackiness and adhesive strength were poor. g. Effect of the Invention The block copolymer composition of the present invention is excellent in blocking resistance, and by adding a tackifier, the tack, because it becomes a pressure-sensitive adhesive excellent in tackiness and holding power,
It can be suitably used for hot-melt type pressure-sensitive adhesives.

Continuation of front page    (72) Inventor Takumi Miyachi               2-11-24 Tsukiji, Chuo-ku, Tokyo Japan               Synthetic Rubber Co., Ltd.                (56) References JP-A-61-171714 (JP, A)                 JP-A-63-89562 (JP, A)                 JP-A-63-86745 (JP, A)

Claims (1)

(57) [Claims] (A) the general formula [(A-B ₁₎ l _1] m-Y ₁ (In the formula, A an aromatic vinyl polymer block, B ₁ having a molecular weight of 10,000 to 30,000 is a conjugated diene polymer block,
l ₁ is an integer of 1 to 3, m is an integer from 2 to 4, Y ₁ represents a residue of a coupling agent other than tin coupling agent. Block copolymer 20 to 60 wt%, represented by), (B) the general formula [(A-B ₂₎ l _2] n-Y ₂ (wherein, A represents an aromatic vinyl molecular weight 10,000 to 30,000 heavy Coalescing block, B ₂ is a conjugated diene polymer block,
l ₂ represents an integer of 1 to 3, m represents an integer of 2 to 4, and Y ₂ represents a residue of a tin-based coupling agent. Block copolymer 50 to 10 wt%, represented by), and (C) the general formula _{(A-B 3) l 3} ( In the formula, A an aromatic vinyl polymer block having a molecular weight of 10,000 to 30,000, B ₃ Is a conjugated diene polymer block;
(B) than the molecular weight of the conjugated diene polymer block B ₂ components
Conjugated diene polymer block 1.2 times or more, l ₃ is 1 to
Indicates an integer of 3. ) 10 to 50% by weight of a block copolymer represented by the following formula: 2. (A) the general formula [(A-B ₁₎ l _1] m-Y ₁ (In the formula, A an aromatic vinyl polymer block, B ₁ having a molecular weight of 10,000 to 30,000 is a conjugated diene polymer block,
l ₁ is an integer of 1 to 3, m is an integer from 2 to 4, Y ₁ represents a residue of a coupling agent other than tin coupling agent. Block copolymer 20 to 60 wt%, represented by), (B) the general formula [(A-B ₂₎ l _2] n-Y ₂ (wherein, A represents an aromatic vinyl molecular weight 10,000 to 30,000 heavy Coalescing block, B ₂ is a conjugated diene polymer block,
l ₂ represents an integer of 1 to 3, m represents an integer of 2 to 4, and Y ₂ represents a residue of a tin-based coupling agent. Block copolymer 50 to 10 wt%, represented by), and (C) the general formula _{(A-B 3) l 3} ( In the formula, A an aromatic vinyl polymer block having a molecular weight of 10,000 to 30,000, B ₃ Is a conjugated diene polymer block;
(B) than the molecular weight of the conjugated diene polymer block B ₂ components
Conjugated diene polymer block 1.2 times or more, l ₃ is 1 to
Indicates an integer of 3. 20 to 300 parts by weight of a tackifier and 0 to 200 parts by weight of a softener with respect to 100 parts by weight of a block copolymer composition comprising 10 to 50% by weight of a block copolymer represented by the formula: Block copolymer composition.