JPH0931437A - Hot melt adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a hot melt adhesive composition which contains a specific ethylene copolymer, a tackifying resin and a specific wax in a specific proportion, shows improved adhesion to polyester substrate and an improved solidifying rate and is suitable for adhesion between polyesters or of the same to a metal. SOLUTION: This hot melt adhesive comprises (A) 5-94wt.% of an ethylene- carbon monoxide unsaturated carboxylic ester copolyer (for example, a terpolymer with a melt flow rate of 0.1-3,000g/10min. under 2.16kg load at 190 deg.C and comprising monomers of 30-95wt.% of ethylene, 3-20wt.% of carbon monoxide and 2-50wt.% of an unsaturated carboxylic ester), (B) 1-90wt.% of a tackifier such as a rosin and (C) 0-40wt.% of a normal paraffin wax purified in the carbon number ranging from 28-46.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a hot-melt adhesive composition having excellent adhesion to a polyester adherend, which is said to have poor adhesion.

[0002]

2. Description of the Related Art Hot-melt adhesives are economically used in the process of instant bonding and high-speed bonding without solvent, and are therefore widely used in the fields of packaging, bookbinding, plywood, woodworking, etc. ing. However, when the adherend has a small number of functional groups in its molecular structure, such as polyester or a polyester-coated adherend, it is extremely difficult to bond the adherend. For example, in JP-A-55-154235, AB-
A block copolymer (A is a monovinyl aromatic hydrocarbon,
B is a hot-melt adhesive consisting of a base polymer consisting of a conjugated diene or a rubber-like mono-olefin), a tackifying resin and a wax. In the hot-melt adhesive, the adhesiveness to polyester is satisfactory. However, there are problems that the melt viscosity is high and coating is difficult, and that the solidification rate after coating is too long, making it unsuitable for high-speed production lines.

[0003]

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a hot melt adhesive composition which is particularly excellent in adhesive strength to polyester and has a fast solidification rate.

[0004]

The hot-melt adhesive composition of the present invention comprises an ethylene / carbon monoxide / unsaturated carboxylic acid ester copolymer 5 to 94% by weight and a tackifying resin 1 to
It is characterized by comprising 90% by weight and 1 to 40% by weight of normal paraffin wax refined to have 28 to 46 carbon atoms.

The ethylene / carbon monoxide / unsaturated carboxylic acid ester copolymer used in the present invention is a random copolymer obtained by randomly copolymerizing ethylene, carbon monoxide and an unsaturated carboxylic acid ester. The unsaturated carboxylic acid ester is preferably an α, β-unsaturated carboxylic acid ester, and specifically, acrylic acid, methacrylic acid, maleic acid or the like is used as the α, β-unsaturated carboxylic acid component. The alcohol component constituting the ester is preferably a linear or branched alcohol having about 1 to 10 carbon atoms, specifically, methanol, ethanol, isopropanol, n-propanol, isobutanol, sec-butanol, n-hexanol. , N-octanol, 2-ethylhexanol, n-decanol and the like are used. Specific examples of the unsaturated carboxylic acid ester include methyl (meth) acrylate,
Ethyl (meth) acrylate, isobutyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, phenyl (meth) acrylate, dimethyl maleate and the like are used. Among these, it is preferable to use a primary ester of acrylic acid.

In the above ethylene / carbon monoxide / unsaturated carboxylic acid ester copolymer, ethylene, carbon monoxide,
The ratio of unsaturated carboxylic acid ester is ethylene 3
0 to 95% by weight, carbon monoxide 3 to 20% by weight, and unsaturated carboxylic acid ester 2 to 50% by weight are preferable. By copolymerizing each monomer with the above composition, compatibility with other tackifying resins can be obtained, and the adhesive strength to an adherend, which is said to be difficult to adhere, can be maintained. When the compounding ratio of carbon monoxide is less than 3% by weight, the adhesive force tends to be lowered, and when it exceeds 20% by weight, the weather resistance stability tends to be poor and the field of use tends to be restricted. Furthermore, the above-mentioned ethylene, carbon monoxide,
Unsaturated carboxylic acid ester copolymer is 190 ° C., 216
Melt flow rate at 0g load is 0.1-300
Those of 0 g / 10 minutes are preferably used.

The above ethylene / carbon monoxide / unsaturated carboxylic acid ester copolymer generally has a reaction temperature of 150 to 2
It can be obtained by radical copolymerization by a bulk polymerization method under the conditions of 50 ° C. and a reaction pressure of 500 to 3000 kg / cm ² , but it may be produced by solution polymerization or emulsion polymerization.

The ethylene / carbon monoxide / unsaturated carboxylic acid ester copolymer is blended in the hot melt adhesive composition for polyester adhesion in an amount of 5 to 94% by weight. When the content is 5% by weight, the hot melt adhesive obtained does not exhibit sufficient adhesive strength, and when it exceeds 94% by weight, the melt viscosity becomes too high and coating becomes difficult.

The tackifying resin used in the present invention is not particularly limited as long as it is generally used in the related field of hot melt adhesives, and examples thereof include aliphatic hydrocarbon resins and alicyclic resins. Examples include group-based hydrocarbon resins, aromatic-based hydrocarbon resins, polyterpene-based resins, rosin-based resins, styrene-based resins, and coumarone-indene-based resins. Examples of the aliphatic hydrocarbon resin include polymers having 1 to 5 butene, isobutylene, butadiene, 1,3-pentadiene, isoprene, piperidine, etc. as the main component of mono- or diolefins having 4 to 5 carbon atoms. . Examples of the alicyclic hydrocarbon resin include a resin obtained by polymerizing a diene component in a petroleum fraction having 4 to 5 carbon atoms after cyclization dimerization,
Examples thereof include a resin obtained by polymerizing a cyclized monomer such as cyclopentadiene and a resin obtained by internally hydrogenating an aromatic hydrocarbon resin. Examples of aromatic hydrocarbon resins include vinyltoluene, indene, α-methylstyrene and the like having 9 carbon atoms.
Resins containing 10 to 10 vinyl aromatic hydrocarbons as main components can be mentioned. Examples of polyterpene resins include α-pinene polymers, dipentene polymers, terpene-phenol copolymers, α-pinene-phenol copolymers and the like. Examples of rosin-based resins include gum rosin, wood rosin, rosin such as tall oil or modified products thereof,
Examples of the modified product include those subjected to modification means such as hydrogenation, disproportionation, dimerization and esterification. Examples of the rosin ester include esters such as ethylene glycol, diethylene glycol, glycerin and pentaerythritol. Examples of styrene-based resin, styrene,
Polymers such as methylstyrene, α-methylstyrene and isopropenyltoluene may be mentioned.

The tackifying resin exemplified above may be graft-modified with maleic anhydride, maleic acid ester or the like. Among the tackifier resins exemplified above, a rosin-based resin and a terpene-based resin are considered considering the compatibility with the ethylene / carbon monoxide / unsaturated carboxylic acid ester copolymer.
It is preferable to select from a phenol copolymer, an aromatic hydrocarbon resin and a polystyrene resin.

The tackifying resin is blended in the hot melt adhesive composition in an amount of 1 to 90% by weight. If it is less than 1% by weight, the temperature characteristic of the obtained hot-melt adhesive cannot be obtained and the adhesive force is not expressed. If it exceeds 90% by weight, the obtained hot-melt adhesive becomes brittle and cold resistance becomes poor.

The carbon number used in the present invention is 28 to
As for the normal paraffin wax purified to 46, a low molecular weight wax having a small carbon number adversely affects the heat resistance, and a high molecular weight wax having a high carbon number adversely affects the compatibility with the tackifying resin. Normal paraffin wax that has been consciously removed to refine the carbon number to 28 to 47. Therefore, when the carbon number of the normal paraffin wax is less than 28, the heat resistance of the obtained hot-melt adhesive becomes poor, and when it exceeds 47, the compatibility with the tackifying resin becomes poor. The normal paraffin wax also includes a normal paraffin wax having a peak in the carbon number distribution of 28 to 47. High-purity refined wax having a narrow carbon number distribution is preferable, and examples thereof include high-purity refined normal paraffin wax in which the purity of normal paraffin wax having 36 carbon atoms is 90% or more.

The normal paraffin wax refined to have 28 to 46 carbon atoms is blended in the hot melt adhesive composition in an amount of 1 to 40% by weight. If the amount is less than 1% by weight, the viscosity and the rapid solidification of the obtained hot melt adhesive are deteriorated, and if it exceeds 40% by weight, the adhesive force of the obtained hot melt adhesive is not exhibited.

[0014] The hot melt adhesive composition of the present invention includes:
Wax other than normal paraffin wax refined to have a carbon number of 28 to 46 as necessary, an antioxidant,
Other components such as various stabilizers, pigments, dyes, oils, plasticizers, and inorganic fillers can be added, but the above-mentioned "ethylene / carbon monoxide / unsaturated carboxylic acid ester copolymer""tackifier" Each weight% of the "resin""normal paraffin wax purified to 28 to 46 carbon atoms" in the present invention is not affected by the above-mentioned other components.

The antioxidant is not particularly limited as long as it is generally used in the related field of hot melt adhesives, and for example, 2,6-di-ter.
-Butyl-4-methylphenol, 2-ter-6-
(3'-ter-butyl-5-methyl-2'-hydroxybenzyl) -4-methylphenyl acrylate, 3,
9-bis {2- [3- (3-ter-butyl-4-hydroxy-5-methylphenyl) propynyloxy] -1-1
-Dimethylethyl} 2,4,8,10-tetraoxaspiro- (5,5) adekane, pentaerythrityl-tetrakis [3- (3,5-di-ter-butyl-4-hydroxyphenyl) propionate], 2,4-bis-
(N-octylthio) -6- (4-hydroxy-3,5
-Di-ter-butylaniline) 1,3,5-triazine, triethylene glycol-bis- [3- (3-te
r-Butyl-5-methyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-te
r-Butyl-4-hydroxyphenyl) propionate], 1,3,5-trimethyl-2,4,6-tris (3,5-di-ter-butyl-4-hydroxybenzyl) benzene, 2,4-bis Examples thereof include phenolic antioxidants such as-[(octylthio) methyl] -o-cresol. Of these, pentaerythrityl-tetrakis [3- (3,5-di-ter-butyl-4-hydroxyphenyl) propionate] is preferable.

The above antioxidant is blended in an amount of 0.01 to 3 parts by weight based on 100 parts by weight of the hot melt adhesive composition of the present invention. If it is less than 0.01 part by weight, the resulting hot-melt adhesive has no effect on heat stability, and if it exceeds 3 parts by weight, the compatibility may deteriorate.

Examples of the above various stabilizers include fatty acid salts of metals of group Ia or group II of the periodic table, and examples of metals of group Ia or group II of the periodic table include calcium, zinc,
Examples of the alkali metal or alkaline earth metal such as magnesium, sodium, potassium, antimony and tin and the fatty acid salt include higher fatty acid salts such as stearic acid, ricinoleic acid, palmitic acid and pyrocatecholic acid.
Calcium stearate is preferably used from the viewpoint of the thermal stability of the obtained hot melt adhesive.

The above-mentioned various stabilizers are blended in an amount of 0.01 to 3 parts by weight based on 100 parts by weight of the hot melt adhesive composition of the present invention. If it is less than 0.01 parts by weight, the effect of the heat stability of the obtained hot melt adhesive is not exerted, and if it exceeds 3 parts by weight, the compatibility is deteriorated and the obtained hot melt adhesive is hindered.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below with reference to Examples. The raw material resins and compounds used in the examples and comparative examples, the method for preparing the composition, the test method, etc. are as follows.

(1) Raw material resin and compound [Ethylene / carbon monoxide / unsaturated carboxylic acid ester copolymer] ○ Ethylene / carbon monoxide / n-butyl acrylate copolymer; n-butyl acrylate = 30 % By weight carbon monoxide = 10% by weight MFR = 100 g / 10 minutes

[Tackifying Resin] Rosin ester “Super Ester A100” manufactured by Arakawa Chemical Co., Ltd. • Terpene-phenol resin “YS Polystar T100” manufactured by Yasuhara Chemical Co., Ltd.

[Normal paraffin wax refined to have 28 to 46 carbon atoms] High-purity refined wax "HNP-9" manufactured by Nippon Seiro Co., Ltd.

[Others] ○ Hindered phenolic antioxidant "Irganox 1010" manufactured by Ciba-Geigy ○ Phosphorus antioxidant; "Irgafos 168" manufactured by Ciba-Geigy ○ Calcium stearate manufactured by Wako Pure Chemical Industries ○ Synthetic wax manufactured by Sazole "Sazol H1" ○ Natural wax Carnauba wax

(2) Method for preparing hot melt adhesive Ethylene / carbon monoxide / unsaturated carboxylic acid ester copolymer, tackifying resin, normal paraffin wax refined to have 28 to 46 carbon atoms, and optionally hindered 1,000 g of a mixture prepared by mixing a phenolic antioxidant, calcium stearate and other compounds in a predetermined amount with 2 parts.
It was placed in a liter beaker and melt-stir-mixed at 180 ° C. for 1 hour to obtain a hot-melt adhesive.

(3) Preparation of hot-melt adhesive test piece The obtained hot-melt adhesive was used to obtain a thickness of 25 μm using a hot-melt open time tester (manufactured by Asahi Kasei Corp.).
m polyethylene terephthalate (“Lumirror” manufactured by Toray Industries, Inc. 50 mm × 100 mm) at a coating temperature of 180 ° C., a coating amount of 0.03 g / cm ² , a coating speed of 7.5 m / mim, an open time of 2 seconds, and a press load of 2 kg. This was used as a test piece.

(4) Test Method 1, Adhesive Strength The obtained test piece was cut into a size of 25 mm × 100 mm, and the T-type peel strength was measured at a pulling speed of 100 mm / mim. The measurement was performed at 20 ° C.

2, solidification time The obtained test piece was subjected to a predetermined time (2, 4, 6, 8, 10 seconds)
After the placement, T-type peeling was performed with a load of 700 g, and the time until peeling did not occur was defined as the solidification time.

1. Melt viscosity The melt viscosity of the obtained hot melt adhesive was measured by a Brookfield viscometer according to JIS-K-6862 under the conditions of 180 ° C. and a rotation speed of 6 min ⁻¹ . In addition,
The rate of change was calculated by comparison with the viscosity after 180 ° C. for 96 hours.

2. Coloring After the hot melt adhesive thus obtained was left in a hot air dryer at 180 ° C. for 96 hours, it was visually evaluated using a Gardner scale in the molten state. The smaller the number, the yellower, the larger the darker it is. The darker it is, the more likely it is to oxidize.

3. Film formation After the obtained hot melt adhesive was left in a hot air dryer at 180 ° C. for 96 hours, it was visually evaluated whether a film was formed on the surface of the melt. It is judged that the more the film is coated, the poorer the thermal stability is.

Examples 1 to 5 and Comparative Examples 1 to 5 A hot melt adhesive was prepared by the above method using 1,000 g of a mixture compounded as shown in Tables 1 and 2.
The obtained hot melt adhesives were used in Examples 1 to 3 and Comparative Example 1.
The adhesive strength and the solidification time were evaluated for Nos. 2 to 2, and the melt viscosity, the coloring, and the film tension were evaluated by the above methods for Examples 4 to 5 and Comparative Examples 3 to 5. The results are shown in Tables 1 and 2.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

According to the present invention, the ethylene / carbon monoxide / unsaturated carboxylic acid ester copolymer has 28 to 20 carbon atoms.
By blending 46 with a purified normal paraffin wax, the adhesive force to the adherend of polyester, which is said to be difficult to adhere, and the solidification rate were improved. Furthermore, by blending an antioxidant and various stabilizers, it is possible to obtain a hot melt adhesive composition having excellent thermal stability even when used at high temperatures. Taking advantage of such characteristics, the hot-melt adhesive composition for polyester adhesion of the present invention can be suitably used for the same polyester and the adhesion between the polyester and the metal.

Claims (1)

[Claims] 1. An ethylene / carbon monoxide / unsaturated carboxylic acid ester copolymer 5 to 94% by weight, a tackifying resin 1 to
A hot melt adhesive composition comprising 90% by weight and 1 to 40% by weight of normal paraffin wax refined to have 28 to 46 carbon atoms.