JPS63268782A - Adhesive - Google Patents

Abstract

PURPOSE:To obtain an adhesive, consisting essentially of an ethylenic copolymer consisting essentially of specific two kinds of repeating units randomly arranged in the form of a linear chain in a specific proportion, having excellent adhesive strength, satisfying thermal stability and even flexibility at low temperatures and useful for metal, wood, plastics, etc. CONSTITUTION:The aimed adhesive consisting essentially of an ethylenic copolymer containing (A) repeating units expressed by formula I and (B) repeating units expressed by formula II (R<1> is H, halogen, 1-20C alkyl, 3-20C alkenyl, 3-20C cycloalkyl, 6-20C aryl or 7-20C aralkyl; R<2> is H, 1-20C alkyl, 3-20C alkenyl, 3-20C cycloalkyl, 6-20C aryl or 7-20C aralkyl) randomly arranged in the form of a linear chain and containing 0.001-45mol.% component (B).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an adhesive containing an ethylene copolymer as a main component. Specifically, the present invention relates to an adhesive whose main component is an ethylene copolymer having a straight polymethylene chain randomly containing unsaturated fatty acids or ester units thereof.

[Prior art and problems to be solved by the invention] Metal, wood, paper, Ia fiber, plastic, rubber.

Adhesives used for various articles such as glass are selected from a wide variety of adhesives such as epoxy-based, polyurethane-based, nitrile rubber-based, acrylic-based, and vinyl acetate-based adhesives depending on the purpose of use.

Among these adhesives, hot-melt adhesives that are melted and flowed by heating and assimilated by cooling are attracting attention because of their excellent workability.For example, ethylene-vinyl acetate adhesives and ethylene-acrylic acid ester copolymer Systematics are often used.

Traditionally, adhesives based on ethylene-unsaturated fatty acid ester copolymers with branched molecular chains, such as ethylene-acrylic acid ester copolymers, have excellent thermal stability and flexibility at low temperatures. However, there was a problem in that the adhesive strength was not sufficient.

[Means for Solving the Problems] An object of the present invention is to provide an excellent adhesive that has improved the above-mentioned problems. That is, the repeating unit [A] represented by the formula and [where R' is a hydrogen atom, a halogen atom, and a carbon number of 1 to 2]
R
2 is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, and 3 carbon atoms
-20 alkenyl group, C3-20 cycloalkyl group, C6-20 aryl group, or C7-2
0 aralkyl group. ] The repeating units [B] represented by are arranged randomly and linearly, and the content ratio of the repeating units [B] is 0.
．． 001 to 45 mol% of an ethylene copolymer as a main component.

The ethylene copolymer, which is the main component of the adhesive of the present invention, consists of a repeating unit [A] (i.e., ethylene unit) represented by the above-mentioned formula [I] and a repeating unit [B] (i.e., It consists of two types of repeating units (units of unsaturated fatty acids or esters thereof), and both repeating units are arranged randomly and linearly. In other words, the ethylene copolymer used in the present invention has no long chain branches and has almost no block copolymerized portions.

Further, the ethylene copolymer used in the present invention has a repeating unit [B] content of 0.001 to 45 mol%, preferably 0.1 to 30 mol%. Although any molecular weight can be used, those having a weight average molecular weight of 5,000 or more are preferable.

In addition, the above formula [■! The repeating unit [B] represented by [B] varies depending on the types of R1 and R2, but specifically, it is an acrylic acid unit or a methyl acrylate unit.

Ethyl acrylate unit, n-propyl acrylate unit, 1-propyl acrylate unit, n-butyl acrylate unit, 1-butyl acrylate unit, acrylic acid-
t-butyl unit, n-hexyl acrylate unit, n-octyl acrylate unit, 2-ethylhexyl acrylate unit.

Benzyl acrylate unit, methacrylic acid unit, methyl methacrylate unit, ethyl methacrylate unit, n-propyl methacrylate unit, 1-propyl methacrylate unit, 〇-butyl methacrylate unit, 1-methacrylate unit
-butyl unit, 7-butyl methacrylate unit, 2-ethylhexyl methacrylate unit, phenyl methacrylate unit, methyl α-chloroacrylate unit, ethyl α-chloroacrylate unit or methyl α-phenylacrylate unit, etc. be.

Various methods can be considered to produce the ethylene copolymer, which is the main component of the adhesive of the present invention, but usually ethylene and unsaturated fatty acids or their esters are used as raw materials, and ethylene copolymers are processed in the presence of a Lewis acid. It is obtained by copolymerization using a catalyst containing a compound and an organometallic compound as main components.

Specific examples of unsaturated fatty acids or esters thereof used in the present invention include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and α-chloroacrylic acid, methyl acrylate,
Ethyl acrylate, propyl acrylate, butyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate.

Acrylic esters such as benzyl acrylate; α-substituted acrylics such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, phenyl methacrylate, methyl α-chloroacrylate, and ethyl α-chloroacrylate; Examples include acid esters.

Next, specific examples of the Lewis acid used in the present invention include aluminum chloride, aluminum bromide, ethylaluminum dichloride, diethylaluminium chloride, and the like.

Furthermore, specific examples of chromium compounds and organometallic compounds used as catalysts will be given. Examples of chromium compounds include chromium carboxylates such as chromium acetate, chromium stearate, and chromium benzoate, chromium such as tetramethoxychromium, tetraethoxychromium, tetra-n-butoxychromium, triethoxychromium monochloride, and jetoxychromium dichloride. Alkoxy compounds, chromium chelate compounds such as chromium trisacetylacetonate, chromium tris(2-methyl-1,3-butanedioate), chromium tris(1,3-butanedioate), biscyclopentadienylchromium, bisbenzenechromium, Monochromium π-complexes such as diphenylbenzenechromium and dihexamethylbenzenechromium, chromium aryl compounds such as diphenylchromium and tetraphenyltristetrahydrofuranchromium, chromium trichloride, chromium tribromide, chromium triiodide, chromium dichloride, Examples include one or more compounds selected from chromium halides such as chromium bromide.
As the organometallic compound, organometallic compounds of Groups 1 to 2 of the periodic table are used, and specific examples include methyllithium, ethyllithium, diethylmagnesium, ethylbutylmagnesium, trimethylaluminum, triethylaluminum, diethylaluminum chloride, etc. can give.

Furthermore, depending on the copolymerization conditions, in addition to the repeating units [A] and [B], linear polymethylene chains with ethyl branches are also produced, which are also the main components of the adhesive of the present invention. Since it exhibits the same performance as a certain ethylene copolymer, at least the repeating units [A] and [B]
Any copolymer having the following may be used.

Substrates that can be bonded using the adhesive of the present invention include metals such as aluminum, lead, iron, magnesium, beryllium, and titanium, polyethylene, polypropylene, poly-3-methylbutene-1, poly-4-methyl Polyolefins such as Penten-1, plastics such as nylon and polyester, alloys such as brass and stainless steel, plated surfaces such as gold and silver, others, paper, glass,
Anything that has a solid surface that can be bonded, such as cloth, wood, leather, ceramic, and rubber, may be used. Adhesion between the above substrate and the copolymer of the present invention, and adhesion between the same and different types of the above substrates is possible.

The adhesive of the present invention may be used in a hot melt type or a solvent volatilization type.

When used as a hot melt type, melt extrusion lamination coating or dry lamination coating.

After laminating the copolymer of the present invention and a base material by a commonly used method such as sand laminate coating, a known heat sealing method using a heating bar, heating rod, wire, shoe, iron, roller, high frequency, ultrasonic wave, etc. Heat seal.

Furthermore, when adhering plastic substrates, it is preferable to subject the coating surface to corona treatment, ozone treatment, or the like.

When used as a hot melt, tackifiers, plasticizers, softeners, fillers, etc. can be blended in with a conventional method, if necessary. As tackifiers, rosin, rosin derivatives, terpene resins, etc. are used, and as plasticizers and softeners, polybutene, DOP, DBP,
Examples of fillers include liquid rosin ester, low-molecular styrene resin, and chlorinated paraffin, and examples of fillers include talc, clay, calcium carbonate, barium carbonate, and barium sulfate.

When used as a solvent volatilization type, the ethylene copolymer used in the present invention can be used in chloroform, methylene chloride, heptane,
After it is dissolved in a solvent such as toluene and applied to a base material, the solvent is evaporated by heating or other methods to exhibit adhesive strength.

It is also possible to bond by a method such as a heat sealing method after volatilizing the solvent.

Furthermore, when adhering metals, etc., it is desirable to clean and activate the surface and perform pretreatments such as degreasing and pickling in order to increase the adhesion force.

[Example] Next, the present invention will be explained in detail with reference to examples.

Example 1 Production of Tei copolymer After replacing the inside of the autoclave with argon, toluene 40
0 mJ and ball milled aluminum chloride 13.3
3 g of toluene slurry was added, and 18.43 g of 2-ethylhexyl acrylate was added dropwise at 10°C.
The reaction was allowed to proceed for 0 minutes. After the reaction was completed, 40 mmol of diethylaluminium chloride and chromium acetate anhydride (equivalent to 1 mmol as chromium atoms) were added as catalyst components. This was heated to 50℃ and hydrogen gas was added at 0.5kg/
cm'·G, and then ethylene was introduced at 9°5 kg/cm2·G. The total pressure of ethylene is 10k
The reaction was carried out for 3 hours by continuously introducing the solution so as to maintain the concentration of g/cm'·G.

After the reaction was completed, the copolymer was deashed with a hydrochloric acid-methanol mixture, washed with methanol, and then extracted with acetone to remove the amorphous polymer.

The white copolymer thus obtained weighed 21.4 g, and its infrared absorption spectrum showed absorption due to ester bonds at 1730 cm-' and 1160 cm''. The content of 2-ethylhexyl acrylate units in the copolymer calculated from the absorbance ratio of methylene chains and carbonyl groups was 16.1 mol %. In addition, the melting point according to differential thermal analysis is 116°C, and the melting point of polyethylene is 134°C.
C. This is because 2-ethylhexyl acrylate is randomly introduced into the ethylene chain in a crystal-disturbed manner. The melt index of this copolymer is 9.7 g/g at 190°C.
It was lo minutes.

(2) Measurement of Adhesive Strength The copolymer obtained in (1) above was molded into a sheet with a wall thickness of 1 inch, and a test piece measuring 50 mm in length and ts mm in width was prepared. This test piece was used as an aluminum plate of the same shape (wall thickness 50#Lm).
Heat sealed against. Heat sealing condition is width 1
Using a 0mm sealer, pressure 2 kg/cm2・G
, time 3 seconds, temperature 120℃, 160℃ or 220℃
The heating was done on the aluminum plate side.

Next, this heat-sealed test piece was subjected to a T-peel test using a tensile tester at a tensile speed of 25 m+a/min. These tests were repeated five times and the average values are shown in Table 1.

Table 1 Example 2 (1) Production of copolymer In Example 1 (1), the reaction conditions were changed to 800ml of toluene.
j, 2-ethylhexyl acrylate 33.9 g, aluminum chloride 24.5 g, diethylaluminium chloride 74 mmol, chromium catalyst component 2 mmol, ethylene partial pressure 9, 7 kg/cm'・G, hydrogen gas partial pressure 0.3
The same operation as in Example 1 (1) was performed except that the weight was set to kg/cm''·G.

As a result, the yield of copolymer was 35. Sg, the content of 2-ethylhexyl acrylate units is 18.6 mol%, the melting point is 115°C, the melt index (190°C
) was 0.0024g 710 minutes.

(2) Measurement of adhesive strength The same operation as in (2) of Example 1 was carried out at a heat-sealing temperature of 22
It was carried out at 0°C. As a result, the seal strength is 15,300g/
The aluminum plate broke at 15+nm.

Example 3 (1) Production of copolymer The reaction conditions in Example 1 (1) were as follows: 0.96 g of acrylic acid as the unsaturated fatty acid, 26.8 mmol of ethylaluminum dichloride as the Lewis acid, and diethyl as the catalyst component. Aluminum chloride 14 mmol 5 Chromium catalyst component 0.2 mmol, ethylene partial pressure 8 kg/
The same operation as in Example 1 (1) was performed except that the hydrogen partial pressure was 2 kg/cm2-G and the hydrogen partial pressure was 2 kg/cm2-G.

As a result, the yield of the copolymer was 4.7 g, the content of acrylic acid units was 1.43 mol%, the melting point was 129°C,
The melt index (190°C) was 0.2 g 710 minutes.

(2) Measurement of adhesive strength In (2) of Example 1, the thickness of the sheet was 200 Pm.
The same operation as in Example 1 (2) was performed except that the heat sealing temperature was only 220°C.

As a result, the seal strength was 550 g and 715 mm.

Example 4 (1) Production of copolymer In Example 1 (1), the reaction conditions were as follows: 2.67 g of ethyl acrylate as the unsaturated fatty acid ester, 3.56 g of aluminum chloride as the Lewis acid, and stearic acid as the chromium catalyst component. The same operation as in Example 1 (1) was performed except that chromium atoms were changed to 0.2 mmol.

As a result, the yield of the copolymer was 3.71 g, the content of ethyl acrylate units was 1.76 mol%, and the melting point was 1.
29℃, melt index (190t) is 0.58g
/10 minutes.

(2) Measurement of adhesive strength In (2) of Example 1, the sheet thickness was set to 200) Lm.
.

The same operation as in Example 1 (2) was performed except that the heat sealing temperature was only 220°C. As a result, the seal strength was 467 g and 715 mm.

Example 5 (1) Production of copolymer In Example 1 (1), the reaction conditions were as follows: 2.67 g of ethyl acrylate as the unsaturated fatty acid ester, 5.33 g of aluminum chloride as the Lewis acid, and chromium tris as the chromium catalyst component. The same operation as in Example 1 (1) was performed except that the amount of acetylacetonate was 0.2 mmol as a chromium atom.

As a result, the yield of the copolymer was 4.7 g, the content of ethyl acrylate units was 2.76 mol%, and the melting point was 12
5℃, melt index (190℃) is 0.12g7
It was 10 minutes.

(2) Measurement of adhesive strength In (2) of Example 1, the sheet thickness was 200 pm.

The same operation as in Example 1 (2) was performed except that the heat sealing temperature was only 220°C. As a result, the seal strength was 477 g and 715 mm.

Comparative Example 1 Ethylene-ethyl acrylate copolymer with branched polymer chains obtained by high-pressure polymerization method (manufactured by Nikki Kogyo Nika):
(2) of Example 1 using a sheet of NUC6220)
The same operation as above was performed to measure the adhesive strength. The content of ethyl acrylate units in this copolymer was 2.1 mol%, and the melt index (190°C) was 4 g/lomin. Further, the seal strength was 80 g and 715 mm.

Comparative Example 2 Ethylene-ethyl acrylate copolymer with branched polymer chains obtained by high-pressure polymerization method (manufactured by Nippon Unicar Aji:
Example 1 using a sheet of [1PDJ 8182)
The same operation as in (2) was performed to measure the adhesive strength. The content of ethyl acrylate units in this copolymer is 4.7 mol%, and the melt index (190°C) is 1.5.
g710 minutes. In addition, the seal strength is 175g/1
5IQL! 1 was enough.

Example 6 The copolymer obtained in Example 1 (1) was used, and in Example 1 (2), a polyethylene terephthalate film (Nilmirror Film T75 manufactured by Toshishima Co., Ltd.) was used instead of the aluminum plate. ) in Example 1 except that (
The same operation as in 2) was performed to measure the adhesive strength. As a result, when the heat sealing temperature is 220℃, the sealing strength is 100g/l! It was znm.

Comparative Example 3 Example 6 except that the ethylene-ethyl acrylate copolymer (DPDJ 8182) of Comparative Example 2 was used in place of the copolymer obtained in Example 1 (1). The same operation was performed. The seal strength in this case is O3
It was 715 mm.

[Effects of the Invention] The adhesive of the present invention has superior adhesive strength and thermal stability compared to conventional adhesives whose main component is an ethylene-unsaturated fatty acid ester copolymer having a branched molecular chain. The properties and flexibility at low temperatures are also satisfactory. In addition, metal
wood, plastic.

Shows excellent adhesion to similar and dissimilar substrates such as rubber, glass, and leather.

Claims (1)

[Claims] Repeating unit [A] represented by the formula - [CH_2-CH_2]- and the formula ▲ Numerical formulas, chemical formulas, tables, etc. ▼ [In the formula, R^1 is a hydrogen atom, a halogen atom, or the number of carbon atoms] 1~
20 alkyl group, an alkenyl group having 3 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms,
R^2 is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 3 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a C 7
~20 aralkyl groups. ] The repeating units [B] represented by are arranged randomly and linearly, and the content ratio of the repeating units [B] is 0.
．． 001 to 45 mol% of an ethylene copolymer as a main component.