JP2884655B2 - Aqueous dispersion - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a novel aqueous dispersion, and more particularly to isopropenyl consisting of a copolymer of isopropenyl toluene and an unsaturated hydrocarbon having 4 to 5 carbon atoms. The present invention relates to an aqueous dispersion of a toluene-based copolymer, and an aqueous dispersion comprising the aqueous dispersion and an acrylic emulsion.

[Conventional technology]

A typical field in which a tackifier is used is the pressure-sensitive adhesive field.

Conventionally, in this field, organic solvent solution-type adhesives have been often used, but since such adhesives use organic solvents, there are problems in terms of safety and health and pollution in the manufacturing process, and such In order to prevent this, a solvent recovery facility was required.

On the other hand, non-organic solvent type, that is, aqueous dispersion of acrylic resin (acryl emulsion) as an aqueous dispersion type pressure-sensitive adhesive
Has also been proposed. Since the aqueous dispersion type adhesive does not use an organic solvent, the problems of safety and health and pollution in the manufacturing process are eliminated, and the equipment for recovering the organic solvent is not required, so that the manufacturing equipment can be simplified. There is. However, the adhesive strength of the aqueous dispersion type adhesive is not sufficient.

In order to improve the adhesive strength of the aqueous dispersion type pressure-sensitive adhesive, a rosin-based tackifier which naturally depends on a raw material is used. On the other hand, attempts have been made to use a petroleum resin obtained from a petroleum fraction having excellent compatibility with an acrylic resin as a tackifier. However, emulsification of petroleum resins is very difficult, and no practically usable aqueous dispersion has been obtained.

[Problems to be solved by the invention]

It is an object of the present invention to provide an aqueous dispersion which imparts excellent tackiness when added to an aqueous dispersion type pressure-sensitive adhesive or adhesive.

Another object of the present invention is to provide an aqueous dispersion comprising the above aqueous dispersion and an acrylic emulsion and having excellent tackiness and adhesive strength.

[Means for solving the problem]

 The present invention is the following aqueous dispersion.

(1) Dispersing an isopropenyltoluene-based copolymer comprising a copolymer of isopropenyltoluene and a saturated hydrocarbon having 4 to 5 carbon atoms in an aqueous medium with a nonionic surfactant of HLB 9 to 15; Aqueous dispersion characterized.

(2) An aqueous solution obtained by dispersing an isopropenyltoluene-based copolymer comprising a copolymer of isopropenyltoluene and an unsaturated hydrocarbon having 4 to 5 carbon atoms with an HLB 9 to 15 nonionic surfactant in an aqueous medium. An aqueous dispersion comprising a dispersion and an acrylic emulsion.

In the present invention, the aqueous dispersions of the above (1) and (2) are used as an aqueous dispersion I, and the aqueous dispersion of the above (3) is used as a dispersion.
Call it II.

As the isopropenyltoluene constituting the isopropenyltolue-based copolymer used in the present invention, ortho-, meta-, or para-isomers and mixtures thereof are used. Isomer 40
It is preferred to use a mixture of 0 to 80% by weight and 0 to 10% by weight of the ortho isomer. Isopropenyltoluene having a purity of 80% by weight or more and containing a small amount of a polymerizable monomer such as styrene, vinyltoluene, α-methylstyrene and the like can also be used. Even if a compound similar to isopropenyltoluene is used instead of isopropenyltoluene, for example, styrene, vinyltoluene, α-methylstyrene, etc., a copolymer having good performance cannot be obtained.

The C4 to C5 unsaturated hydrocarbon constituting the isopropenyltoluene copolymer used in the present invention includes petroleum refining, a fraction containing a C4 to C5 unsaturated hydrocarbon by-produced during cracking. Any fraction selected can be used.

The fraction containing unsaturated hydrocarbons having 4 to 5 carbon atoms by-produced during oil refining and cracking (hereinafter referred to as C ₄ and C ₅ fractions)
A fraction whose boiling point range under normal pressure is usually −15 to + 45 ° C., and 1-butene, isobutylene, 2-butene, 1,1,
It contains polymerizable monomers such as 3-butadiene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 2-pentene, isoprene, 1,3-pentadiene, and cyclopentadiene. In the present invention, any fraction containing polymerizable monomer selected from the C _4, C ₅ fraction, i.e.
C _4, C ₅ fraction of course, C ₄ fraction, C ₄ excluding butadiene
Fraction, can be used C ₅ fraction, C ₅ fraction excluding isoprene, C ₅ fraction and the like excluding cyclopentadiene.

The isopropenyltoluene-based copolymer used in the present invention is the unsaturated hydrocarbon having 4 to 5 carbon atoms as described above with respect to 100 parts by weight of the isopropenyltoluene.
It is obtained by copolymerizing 100 parts by weight. By copolymerizing both at such a ratio, a copolymer having excellent performance as a tackifier can be obtained.

The copolymerization of both components is preferably carried out in the presence of a Friedel-Crafts catalyst.

As the Friedel-Crafts catalyst, known Friedel-Crafts catalysts can be used, and specifically, aluminum chloride, aluminum bromide, dichloromonoethylaluminum, titanium tetrachloride, tin tetrachloride, boron trifluoride, trifluoride, etc. Various complexes of boron oxide and the like can be given.

The amount of Friedel-Crafts catalyst used is the total amount of raw materials
Usually 0.1 to 5 parts by weight, preferably 100 parts by weight, preferably
A range of 0.5 to 3 parts by weight is desirable.

In the copolymerization reaction of both components, the concentration of the polymerizable monomer is 10 to 50% by weight to remove the reaction heat and to suppress the viscosity of the reaction solution.
It is preferable to use a solvent so as to achieve the above degree.

Suitable solvents include, for example, aliphatic hydrocarbons such as pentane, hexane, heptane and octane; alicyclic hydrocarbons such as cyclopentane, cyclohexane and methylcyclohexane; aromatic hydrocarbons such as toluene, xylene, ethylbenzene and mesitylene; And mixtures thereof.

The polymerization temperature varies depending on the raw material composition, but is usually preferably in the range of -50 to + 50 ° C. The reaction time is usually preferably in the range of 10 minutes to 10 hours.

After completion of the polymerization, the catalyst is decomposed with an aqueous alkali solution or methanol, and then washed with water, and unreacted raw materials, solvents, and the like are removed by stripping to obtain the desired isopropenyltoluene-based copolymer. The softening point (ring and ball method) of the copolymer thus obtained is usually 30 to 140 ° C.
It is.

The aqueous dispersion I of the present invention is obtained by dispersing an isopropenyltoluene-based copolymer in an aqueous dispersion. Examples of the aqueous medium include water and a medium containing water as a main component.

The proportion of the isopropenyltoluene-based copolymer contained in the aqueous dispersion I of the present invention is 10 to 80% by weight, preferably
20-70% by weight is desirable. With such a ratio, it is possible to obtain an aqueous dispersion I which is excellent in tackiness, has an appropriate viscosity, and is easy to handle.

In order to disperse the isopropenyltoluene-based copolymer in an aqueous medium, a nonionic surfactant of HLB 9 to 15 is used as an emulsifier.

Addition amount of emulsifier is isopropenyl toluene copolymer
1 to 30 parts by weight, preferably 5 to 20 parts by weight, per 100 parts by weight is desirable. By setting the amount of the emulsifier to be in such a ratio, the aqueous dispersion I having excellent adhesive strength and excellent emulsified state can be obtained.

The aqueous dispersion I of the present invention is produced by dispersing an isopropenyltoluene-based copolymer in an aqueous medium with stirring.

The method of dispersion is not particularly limited, and various known methods can be employed.Normally, the isopropenyltoluene-based copolymer, the emulsifier and the aqueous medium are heated while mixing and stirring to form the isopropenyltoluene-based copolymer. It is preferable to adopt a method of dissolving and dispersing and then lowering the temperature.

The temperature during dissolution and stirring varies depending on the composition of the isopropenyltoluene-based copolymer, but is usually 100 to 200 ° C, preferably 120 to 180 ° C. The stirring time is usually
15 minutes to 3 hours are preferred.

The particle size of the emulsion thus produced is usually 0.1 to 1.5 μm.

Specific examples of the dispersion method include the following (a) direct emulsification method, (b) solvent displacement method, and (c) phase inversion method.

(A) Direct emulsification method A method in which an isopropenyltoluene-based copolymer, an emulsifier and an aqueous medium are added all at once and stirred. When strong stirring is required, a stirrer such as a homomixer may be used. A system in which each component is continuously added to the reactor and continuously withdrawn can be employed, or a batch system using a pressure-resistant autoclave can be employed.

(B) Solvent replacement method A method in which an isopropenyltoluene-based copolymer is dissolved in an appropriate organic solvent in advance, and an aqueous medium is added thereto sequentially or in total, and the organic solvent is removed after stirring. The emulsifier is usually added together with the aqueous medium, but may be added in advance.

(C) Phase inversion method A method of kneading an isopropenyltoluene-based copolymer and an emulsifier, successively adding an aqueous medium to invert the phase, and then emulsifying by adding a large amount of an aqueous medium. When strong kneading is required, use an extruder.

Of these, the direct emulsification method using a pressure-resistant autoclave is preferred.

Additives such as a thickener and an antifoaming agent may be added to the aqueous dispersion I thus obtained, if necessary.

The aqueous dispersion I of the present invention can be used as a tackifier for aqueous dispersion-type pressure-sensitive adhesives and adhesives. The addition of the aqueous dispersion I of the present invention improves the tackiness of the pressure-sensitive adhesive or adhesive, but the heat-sealing further improves the peel strength. Further, by mixing the aqueous dispersion I of the present invention with an acrylic emulsion, an aqueous dispersion II having excellent adhesion to various plastics can be obtained.

Examples of the acrylic emulsion include an emulsion of an acrylate homopolymer, and an emulsion of a copolymer of an acrylate and a methacrylate, vinyl acetate, styrene, acrylonitrile, acrylic acid, and the like. Such an acrylic emulsion is commercially available, and a commercially available product can be used.

The mixing ratio of the aqueous dispersion I and the acrylic emulsion is such that the weight ratio of (isopropenyltoluene copolymer in the aqueous dispersion I) / (resin in the acrylic emulsion) is
It is preferable that the mixing be performed so as to be 5/95 to 80/20, preferably 40/60 to 60/40.

The aqueous dispersion II of the present invention can be used as a pressure-sensitive adhesive, an adhesive, a printing binder, a fiber processing binder, and the like. In particular, an aqueous dispersion II obtained by adding an aqueous dispersion I to an acrylic emulsion mainly containing butyl acrylate or 2-ethylhexyl acrylate (the concentration of the acrylic emulsion is
Aqueous dispersion II (20 to 85% by weight) is used as an adhesive, and aqueous dispersion II (acrylic emulsion having a concentration of 20 to 85% by weight) obtained by adding aqueous dispersion I to an acrylic emulsion mainly containing methyl acrylate or ethyl acrylate is used for printing. binder,
It can be suitably used as a fiber processing binder.

〔The invention's effect〕

According to the present invention, a specific isopropenyl toluene-based copolymer is dispersed in an aqueous medium with a nonionic surfactant of HLB 9 to 15, so that when added to an aqueous dispersion type pressure-sensitive adhesive or adhesive. An aqueous dispersion giving excellent tackiness is obtained.

Further, since the aqueous dispersion and the acrylic emulsion are mixed, an aqueous dispersion excellent in tackiness and adhesive strength can be obtained.

〔Example〕

 Next, examples of the present invention will be described.

Example 1 100 g of isopropenyltoluene (purity: 99.2%) obtained by distillative separation from the acid fission product of cymene hydroperoxide in the cresol production process, and C ₄ containing unsaturated hydrocarbons obtained by pyrolysis of petroleum naphtha , C ₅
10 g of the fraction and 150 g of toluene were charged into an autoclave, and BF ₃ as a catalyst was maintained at 0 ° C. while stirring.
1.5 g of the phenol complex was added dropwise in about 10 minutes. Thereafter, stirring was continued for another 3 hours. Next, 50 ml of a 5% by weight aqueous sodium hydroxide solution was added, and the mixture was vigorously stirred for 30 minutes to decompose the catalyst. Then, the aqueous layer was separated. Was distilled off to obtain 105 g of a light yellow block copolymer as a residue. The composition of the raw material monomers and the properties of the resulting copolymer were as follows.

Isopropenyltoluene composition by weight% o-isopropenyltoluene 5.3 m-isopropenyl toluene 60.4 p-isopropenyltoluene 33.5 cymene 0.8 C _4, C ₅ fraction composition by weight% C ₃ 1.5 Isobutane 0.4 n-butane 1.3 1-butene 10.5 isobutylene 19.8 trans-2-butene 8.7 cis-2-butene 4.4 1,3-butadiene 20.9 n-pentane 5.1 isoprene 5.6 1,3-pentadiene 2.8 cyclopentadiene 3.1 Others (fractions with a boiling point of 80 ° C or lower) 15.9 Properties of the copolymer Hue 1 (Gardner, ASTM D 154-58), softening point 95 ° C
(Ring and ball method), number average molecular weight 730, bromine number 15 (ASTM D 1158
-57).

540 g of the above copolymer, 400 g of water, and 60 g of Emulgen 420 (HLB13.6, manufactured by Kao Corporation, trade name) as a surfactant
Was charged into a pressure-resistant autoclave and mixed and stirred. 150 ℃
Then, the mixture was stirred for 2 hours, cooled with water after the completion, and returned to room temperature. The resulting emulsion had a pH of 5.5, a solids concentration of 59.8% by weight, and a particle size of 1.0 μm.

The above emulsion and acrylic emulsion (Nicazole TS
-805, Nippon Carbide Industrial Co., Ltd., trade name)
The mixture was stirred at a ratio of 50 (weight ratio). This mixture is
It was coated with 10 g / m ² to T film (film thickness 25 [mu] m), 3 at 120 ° C.
After drying for 2 minutes, the sample was pressed and reciprocated on a stainless steel plate using a 2 kg rubber roller at a speed of 300 mm / min for 1 reciprocation to obtain a sample. Using a tensile tester at a tensile speed of 300 mm / min
An 80 ° peel test was performed. Table 1 shows the results.

Example 2 Using the same copolymer as in Example 1, emulgen 420 and emulgen 408 (HLB13.6, HLB13.6) were used as surfactants during emulsification.
An emulsion was obtained in the same manner as in Example 1, except that a 5: 1 mixture (weight ratio) with LB 10.0, both manufactured by Kao Corporation was used.

Next, a peeling test was performed using the above emulsion in the same manner as in Example 1. Table 1 shows the results.

Example 3 In Example 1, the amount of the BF ₃ phenol complex added was changed to 2.1.
A copolymer was synthesized in the same manner as in Example 1 except that g was used. The properties of the obtained copolymer were Hue 1, Softening Point 70 ° C,
The number average molecular weight was 540 and bromination was 10.

This copolymer was emulsified in the same manner as in Example 1. The obtained emulsion had a pH of 5.1, a solid content of 59.6% by weight, and a particle size of 0.5.
It was 6 μm.

Using the above emulsion, a peeling test was performed in the same manner as in Example 1. Table 1 shows the results.

Comparative Example 1 The same copolymer as in Example 1 was used, and as surfactants, rheodol TW-L120, SP-010, SP-L10 (HLB16.7, HLB
Both 4.3 and HLB8.6 were emulsified using Kao Corporation (trade name), but no emulsion was obtained.

Comparative Example 2 A peel test was performed in the same manner as in Example 1 except that the acrylic emulsion used in Example 1 was used alone as an adhesive.
Table 1 shows the results.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-43475 (JP, A) JP-A-52-56189 (JP, A) JP-A-49-118729 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) C08L 25/00-25/02

Claims (2)

(57) [Claims] An isopropenyl toluene copolymer comprising a copolymer of isopropenyl toluene and an unsaturated hydrocarbon having 4 to 5 carbon atoms is dispersed in an aqueous medium with a nonionic surfactant of HLB 9 to 15. An aqueous dispersion, characterized in that: 2. An isopropenyltoluene-based copolymer comprising a copolymer of isopropenyltoluene and an unsaturated hydrocarbon having 4 to 5 carbon atoms is dispersed in an aqueous medium with a nonionic surfactant of HLB 9 to 15. An aqueous dispersion comprising an aqueous dispersion and an acrylic emulsion.