JPH07179559A - Polyurethane having rosin skeleton and polyurethane-based adhesive containing the same - Google Patents

Abstract

PURPOSE:To obtain a polyurethane containing a high-molecular polyol unit having a rosin monoglyceride skeleton and a polyisocyanate compound unit as the main constituent units, excellent in initial adhesion, heat-resistant adhesion, etc., and useful for an adhesive for a plastic molding, etc. CONSTITUTION:This polyurethane contains (A) high-molecular polyol units containing (i) a high-molecular polyol unit synthesized by reacting a glycidyl ester of a rosin with a polybasic acid (e.g. adipic acid) and having a rosin monoglyceride skeleton or (ii) another high-molecular polyol unit synthesized by reacting a glycidyl ester of a rosin, a polybasic acid and a polyvalent alcohol (e.g. ethylene glycol) and having a rosin monoglyceride skeleton and preferably having 500 to 10000 number-average molecular weight and (B) polyisocyanate compound (e.g. 1,5-naphthylene diisocyanate) units as the main constituent units.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyurethane having a rosin skeleton and a polyurethane adhesive containing the polyurethane. Specifically, it contains a novel polyurethane having a rosin skeleton in the inner chain of the molecule, and has excellent adhesiveness to various plastic molded products, metals, wood, rubber, etc., especially excellent initial adhesiveness and heat resistant adhesiveness. The present invention relates to a polyurethane adhesive.

[0002]

2. Description of the Related Art In recent years, a multi-layer composite film obtained by laminating several layers of plastic films such as cellophane, polyethylene, polypropylene, nylon, polyester, vinyl chloride, etc. and metal foils such as aluminum foil has been widely used as packaging materials for foods and the like. . Polyurethane adhesives are generally used as adhesives for such films.

Further, since the polyurethane adhesive has insufficient adhesion to a general-purpose film such as a polyethylene film or a polypropylene film, a tackifier such as rosin ester, ketone resin or styrene oligomer is added to supplement the adhesion. ing. However, since these tackifiers have low molecular weights, they have the drawback of deteriorating the physical properties of the adhesive such as heat resistant adhesiveness.

Further, a rosin ester is blended with a polyurethane polyisocyanate prepolymer obtained by reacting a polyol having a carboxyl group bonded to the main chain via an ester bond with an organic polyisocyanate compound. Attempting to improve the above-mentioned drawbacks of the tackifier by reacting the residual hydroxyl groups of the above with the terminal isocyanate of the prepolymer (JP-A-2-15).
5978). However, even by the method described in this publication, the rosins could not be completely incorporated into the polyurethane molecule, and the physical properties such as heat-resistant adhesion were insufficient.

Further, a polyurethane adhesive using a compound obtained by reacting a diepoxy compound with rosins as a high molecular weight diol component has also been proposed (Japanese Patent Laid-Open Publication No. HEI 5)
-263059). However, in the method described in the publication, since it is essential to use a diepoxy compound, a low molecular weight diepoxy compound must be used when preparing a high molecular weight diol having a high rosin content. As a result, it was difficult to prepare a high molecular weight diol having a high rosin content and a low hydroxyl value (that is, a relatively high molecular weight).

[0006]

The present invention has excellent adhesiveness to various plastic molded articles such as polyester, nylon, polyethylene, polypropylene, etc., and particularly excellent initial adhesiveness and heat resistant adhesiveness. It is an object of the present invention to provide a novel polyurethane having a rosin skeleton which can be used as an adhesive or the like and whose rosin content and molecular weight can be easily adjusted.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above problems, and as a result, previously prepared a high molecular weight polyol having a monoglyceride skeleton of rosins by the following method, It has been found that a specific polyurethane having a rosin skeleton regularly introduced into a side chain in a molecule can be easily obtained by using it as a molecular polyol component. The present invention has been completed based on this new finding.

That is, the present invention is a polyurethane comprising a polymer polyol and a polyisocyanate compound as main constituents, wherein the polymer polyol is
(1) a high molecular weight polyol having a monoglyceride skeleton of a rosin obtained by reacting a glycidyl ester of a rosin and a polybasic acid, or (2) a glycidyl ester of a rosin, a polybasic acid and a polyhydric alcohol A polyurethane having a rosin skeleton, which is characterized by comprising a polymer polyol having a monoglyceride skeleton of the obtained rosins (hereinafter, a polymer polyol having a monoglyceride skeleton of these rosins is referred to as a rosin-modified polymer polyol). And a polyurethane adhesive containing the polyurethane having the rosin skeleton.

In the present invention, (1) a rosin-modified polymer polyol obtained by reacting a glycidyl ester of rosin and a polybasic acid as a polymer polyol component,
Alternatively, (2) it is essential to use a rosin-modified polymer polyol obtained by reacting a glycidyl ester of rosin, a polybasic acid and a polyhydric alcohol.

The glycidyl ester of rosin refers to a reaction product of rosin with epihalohydrin, β-methylepihalohydrin and the like. Examples of rosins include gum rosin, tall oil rosin, wood rosin, disproportionated rosin, hydrogenated rosin, and mixtures thereof. As these rosins, it is preferable to use purified rosins from which unsaponifiable matters and impurities are removed by distillation.

As the polybasic acid, adipic acid, maleic acid, fumaric acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, isophthalic acid, terephthalic acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid,
Dibasic acids such as azelaic acid, sebacic acid and suberic acid,
Examples include tribasic acids such as trimellitic acid, tetrabasic acids such as pyromellitic acid, and corresponding corresponding acid anhydrides, monoesters such as methyl esters and ethyl esters, which can be transesterified, and dimer acids. To be

Polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol,
1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-butanediol, 1,4-butanediol, 1,4-butynediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, cyclohexanedimethanol,
Diols such as 1,6-hexanediol, bisphenol A and hydrogenated bisphenol A; triols such as glycerin, trimethylolethane, trimethylolpropane and glycerin; tetraols such as pentaerythritol and diglycerin; dipentaerythritol and the like Hexaols; and polyoxyalkylene polyols such as polyethylene glycol, polypropylene glycol, polyoxytetramethylene ether glycol, etc. obtained by ring-opening polymerization of ethylene oxide, propylene oxide, tetrahydrofuran, etc. using the polyhydric alcohol as the starting material, Examples thereof include polyester polyols obtained by ring-opening polymerization of lactones such as ε-caprolactone and β-methyl-δ-valerolactone using alcohol as a starting material. Further, in the present invention, polyhydric alcohols such as n-butyl glycidyl ether, alkyl glycidyl ethers such as 2-ethylhexyl glycidyl ether, monocarboxylic acid glycidyl esters such as versatic acid glycidyl ester, styrene oxide,
Epoxy group-containing compounds such as cyclohexane oxide can also be used.

The rosin-modified polymer polyol of the present invention is
For example, it can be manufactured by the following method. In particular,
(1) Glycidyl ester of rosin and polybasic acid,
Alternatively, (2) a predetermined amount of glycidyl ester of rosin, polybasic acid and polyhydric alcohol is simultaneously charged, and 100
A method of promoting esterification under a temperature condition of about 250 ° C. until the acid value becomes 8 or less, preferably 5 or less.

When the glycidyl ester of rosin and a polybasic acid are reacted with (1) the glycidyl ester of rosin and 1 part by mole of glycidyl ester of rosin,
Usually, it means 0.25 to less than 1 part by mole of polybasic acid, (2)
When glycidyl ester of rosin, polybasic acid and polyhydric alcohol are reacted, polybasic acid is usually added in an amount of 0.25 to 5 per 1 mol part of glycidyl ester of rosin.
About 9 parts by mole and about 59 parts by weight or less of polyhydric alcohol. The amounts of the polybasic acid and the polyhydric alcohol used are appropriately determined in consideration of the number average molecular weight, the acid value, the rosin content, etc. of the polymer polyol having a monoglyceride skeleton of the rosin of the present invention to be obtained. In (1), when the proportion of the polybasic acid used is higher than the above proportion, many rosin-modified polymer polyols whose terminals are not hydroxyl groups are not suitable as urethane raw materials. Also in (2), when the proportion of the polybasic acid used is higher than the above proportion, many rosin-modified polymer polyols whose terminals are not hydroxyl groups are produced, and the rosin content is reduced. Further, when the proportion of polyhydric alcohol used is higher than the above proportion, the rosin content is low, which is not preferable.

In the reaction, amine catalysts such as trimethylamine, triethylamine, tributylamine, benzyldimethylamine, pyridine, and 2-methylimidazole, quaternary ammonium salts such as benzyltrimethylammonium chloride, Lewis acid, etc. are not necessarily required in the reaction. It is also possible to use borate, triarylphosphine such as triphenylphosphine, trialkylphosphine, organometallic compounds, organometallic salts and the like.

Thus, the rosin-modified polymer polyol of the present invention is obtained. Further, in the present invention, as the rosin-modified polymer polyol, a polymer obtained by subjecting the rosin-modified polymer polyol as an initiator to ring-opening polymerization of ethylene oxide, propylene oxide, ε-caprolactone or the like may be used. it can.

Next, other constituent components in the present invention will be described. In the present invention, various known polymer polyols can be used in combination with the rosin-modified polymer polyol. The combined ratio may be appropriately determined so that the content of rosins in the resin solid content of the produced polyurethane is in the range of about 3 to 60% by weight. When the content of rosins in the resin solid content of polyurethane is less than 3% by weight, the adhesion to the plastic molded product is insufficient, and when it exceeds 60% by weight, the polyurethane becomes too hard and becomes poor in flexibility. Is also not preferable.

As various known polymer polyols, polyester polyols obtained by the condensation reaction of polyhydric alcohol and polybasic acid described in the section of rosin-modified polymer polyol; ethylene oxide using the polyhydric alcohol as a starting material. Polyoxyalkylene polyols added with propylene oxide, tetrahydrofuran, etc .; Polyesters obtained by ring-opening polymerization of cyclic ester compounds such as ε-caprolactone, β-methyl-δ-valerolactone; Others, polycarbonate polyols, polybutadiene Examples thereof include glycols and acrylic polyols.

The number average molecular weight of the rosin-modified polymer polyol used in the present invention and the number of polymer polyols that can be used in combination are usually about 500 to 10,000. When the number average molecular weight is less than 500, the obtained polyurethane is hard and the adhesiveness is not sufficient, and when the number average molecular weight exceeds 10,000, the viscosity of the obtained polyurethane solution becomes too high and the coatability deteriorates. .

Examples of the polyisocyanate compound include various known aromatic, aliphatic or alicyclic compounds. For example, 1,5-naphthylene diisocyanate,
4,4'-diphenylmethane diisocyanate, 4,
4'-diphenyldimethylmethane diisocyanate,
4,4'-dibenzyl isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate,
Tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, 2,2
4-trimethylhexamethylene diisocyanate, 2,
4,4-trimethylhexamethylene diisocyanate,
Cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,
Typical examples thereof include 4-diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, methylcyclohexanediisocyanate, m-tetramethylxylylene diisocyanate, and dimerisocyanate obtained by converting the carboxyl group of dimer acid into an isocyanate group.

Further, in the present invention, a chain extender may be used in the production of polyurethane. As a chain extender, 2
A low molecular weight compound having one or more active hydrogen atoms can be used. For example, diamines such as ethylenediamine, propylenediamine, hexamethylenediamine, triethylenetetramine, diethylenetriamine, isophoronediamine, dicyclohexylmethane-4,4'-diamine; 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2. -Hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, and other diamines having a hydroxyl group in the molecule; the polyhydric compounds described in the section of the rosin-modified polyester polyol. Representative examples thereof include alcohols and dimer diamines obtained by converting the carboxyl group of dimer acid into an amino group.

If necessary, a chain length terminator may be used. Examples of such chain length terminators include di-
Examples include dialkylamines such as n-butylamine and monohydric alcohols such as ethanol and isopropyl alcohol.

As a method for producing polyurethane, known means can be adopted. For example, a polymer polyol including a rosin-modified polymer polyol and, if necessary, a chain extender and a chain length terminating agent are mixed and heated to about 40 to 100 ° C., and then the number of active hydrogen atoms of these compounds and isocyanate are mixed. The ratio of groups is (equivalent number of isocyanate groups) /
(Equivalent number of active hydrogen of compound having active hydrogen atom) =
A method of producing a polyurethane having an isocyanate group or a hydroxyl group at the terminal by adding a diisocyanate compound in a ratio of about 4.0 to 0.8 and reacting at about 50 to 150 ° C can be mentioned.

The polyurethane can be produced under various conditions in various organic solvents or without solvent. Examples of the organic solvent include ethyl acetate, methyl ethyl ketone, acetone, toluene, methyl cellosolve acetate, ethyl cellosolve acetate, cyclohexane, methyl isobutyl ketone, dioxane, cyclohexanone, tetrahydrofuran, dimethylformamide, and the like. It is usually about 1.0 to 15 times the weight of the solid content. Such an organic solvent is preferably used in the field of the resulting polyurethane, such as an adhesive, which requires a certain high molecular weight.

The number average molecular weight of the obtained polyurethane is
It depends on the intended use and may be appropriately determined according to the intended use, but it is usually selected from the range of about 1000 to 100,000.

The polyurethane having a rosin skeleton thus obtained can be used for various purposes. For example, glue,
It can be applied to printing inks, paints, sealing agents, etc. In particular, the polyurethane having a rosin skeleton of the present invention is suitable as an adhesive because it is excellent in adhesiveness, particularly initial adhesiveness and heat resistant adhesiveness. The case where the polyurethane having a rosin skeleton of the present invention is used as an adhesive will be described below.

When the polyurethane having a rosin skeleton of the present invention is used as a polyurethane-based adhesive, its blending needs to be appropriately determined depending on the type of adherend and the application.

For example, since the use of a solvent is not preferable for an adhesive or the like used for a film for food packaging, a liquid urethane prepolymer produced without using a chain extender and a curing agent are mixed and applied, and then a curing reaction is performed. It is possible to adopt a method of simultaneously performing and bonding. In this case, when the terminal group of the liquid urethane prepolymer is a hydroxyl group, a triisocyanate compound (trimethylol propane or glycerin and tolylene diisocyanate 1: 1 is used as a curing agent.
3 addition product etc.) and the like, and the method of curing is adopted. When the liquid prepolymer has an isocyanate terminal group, a method of adding a polyamine, a polyester polyol, a polyether polyol, a polyol such as an acrylic polyol, or the like as a curing agent, or a method of moisture curing is adopted.

The adhesive of the present invention can also be used as a structural adhesive. In addition, for applications such as wood,
It is advisable to use a moisture-curable oligomer type urethane prepolymer. The urethane prepolymer used as a structural adhesive is generally a one-component type,
If necessary, it may be used as a two-pack type in combination with polyamines or polyols.

[0030]

The novel polyurethane having a rosin skeleton of the present invention is made of polyester, nylon, polyethylene,
Excellent adhesion to various plastic moldings such as polypropylene, especially initial adhesion and heat resistance,
It is useful as a polyurethane adhesive.

Although the reason why the novel polyurethane having a rosin skeleton of the present invention exhibits the above effect is not clear, since the rosin-modified polymer polyol is used as an essential component, the tackifying effect is high. Moreover, it is presumed that the highly hydrophobic rosin skeleton can be regularly introduced into the molecular side chain of polyurethane, and the heat resistance and adhesion are improved. The rosin content in the rosin-modified polymer polyol can be easily adjusted by the amount of polybasic acid or polyhydric alcohol used, and the hydroxyl value, molecular weight, etc. can be appropriately determined according to the application.

[0032]

EXAMPLES The present invention will be specifically described below with reference to production examples, examples and comparative examples, but the present invention is not limited to these examples. Hereinafter, parts and% are by weight unless otherwise specified.

Production Example 1 300 g of a crude disproportionated rosin (acid value 158, softening point 77.0 ° C., color tone Gardner 7) was placed in a round bottom flask equipped with a stirrer, a thermometer, a cooling tube and a nitrogen gas introducing tube. Parts and trimethylamine hydrochloride 0.6 parts with epichlorohydrin 600
In addition to the parts, the mixture was heated to 80 ° C. and kept warm for 3 hours. HLC measurement method (column: ODS (Yamamura Chemical Laboratory Co., Ltd., trade name YMC Pack A-312), solvent: methyl alcohol /, in which halohydrin ester was produced and unreacted disproportionated rosin was removed 0.01 wt% phosphoric acid = 9/1
(Volume ratio), flow rate 1 ml / min, detector: differential refractometer (manufactured by Japan Waters Limited), and then the temperature in the reaction system was raised to 120 ° C. to obtain sodium hydroxide 4
0 part was added in 5 portions over 1 hour. During this time, the produced water was azeotropically removed with epichlorohydrin. Then, the epichlorohydrin was distilled off under reduced pressure, and further 3
It was kept for 30 minutes under the condition of 0 mmHg and 125 ° C.
400 ml of toluene was added to the residue, and the precipitate of sodium chloride was filtered. Toluene was distilled off from the filtrate under reduced pressure, and after further holding at 30 mmHg and 135 ° C. for 5 minutes, 330 parts of rosin glycidyl ester (yield: 92.
8%, purity 83.1%) was obtained. This is a brown viscous liquid with a color tone of Gardner 8 and an epoxy equivalent of 43.
It was 1.

Production Example 2 301.7 parts of rosing lysidyl ester obtained in Production Example 1 and 27 adipic acid were placed in the same round bottom flask as in Production Example 1.
A hydroxyl value of 31.5 KOHm was obtained by charging 1.6 parts and 158.2 parts of 1,6-hexanediol and raising the temperature under a nitrogen stream to finally proceed the esterification at 250 ° C.
g / g, acid value 2.9 KOHmg / g, melt viscosity 340p
s / 50 ° C, number average molecular weight 3560, rosin content 3
0.8% rosin-modified polymeric polyol (A) 652.
5 parts were obtained.

Production Example 3 A round bottom flask similar to that of Production Example 1 was charged with 558.7 parts of rosin lysidyl ester obtained in Production Example 1 and 146 parts of adipic acid, and hydroxyl value was 5 in the same manner as in Production Example 2.
Rosin-modified polymer polyol (B) 66 having 9.3 KOHmg / g, acid value 1.8 KOHmg / g, softening point 71.0 ° C., number average molecular weight 1890, and rosin content 56.1%.
3.5 parts were obtained.

Production Example 4 215.5 parts of rosing lysidyl ester obtained in Production Example 1 and polypropylene glycol (hydroxyl value 266, number average molecular weight 400) 2 were placed in the same round bottom flask as in Production Example 1.
10.9 parts and 128.2 parts of adipic acid were charged, and the hydroxyl value was 29.0 KOHmg / g in the same manner as in Production Example 2.
Acid value 4.7 KOHmg / g, melt viscosity 95.6 ps / 5
0 ° C, number average molecular weight 3870, rosin content 28.0%
To obtain 511.9 parts of the rosin-modified polymer polyol (C).

Example 1 200 parts of the rosin-modified polymer polyol (A) obtained in Production Example 2 and a molecular weight of 2 were placed in the same round bottom flask as in Production Example 1.
2,000 polybutylene adipate diol (200 parts) and isophorone diisocyanate (70.8 parts) were charged and reacted at 100 ° C. for 6 hours under a nitrogen stream to obtain a urethane prepolymer having a free isocyanate content of 2.77%. The rosin content in the resin solid content is 13.1%
Is.

Example 2 350 parts of the rosin-modified polymer polyol (B) obtained in Production Example 3 and a molecular weight of 2 were placed in the same round bottom flask as in Production Example 1.
5,000 polybutylene adipate diol (50 parts) and isophorone diisocyanate (93.6 parts) were charged and reacted at 100 ° C. for 6 hours under a nitrogen stream to obtain a urethane prepolymer having a free isocyanate content of 3.51%. The rosin content in the resin solid content is 39.8%.

Example 3 In the same round bottom flask as in Production Example 1, 200 parts of the rosin-modified polymer polyol (C) obtained in Production Example 4 and a molecular weight of 2 were added.
200 parts of poly (3-methyl-1,5-pentane adipate) diol, isophorone diisocyanate 6
7.7 parts of the resulting mixture was charged and reacted under a nitrogen stream at 100 ° C. for 6 hours to obtain a urethane prepolymer having a free isocyanate content of 2.66%. The rosin content in the resin solid content is 1
It is 2.0%.

Comparative Example 1 A round-bottomed flask similar to that used in Production Example 1 was charged with 500 parts of polybutylene adipate diol having a molecular weight of 2000 and 100 parts of isophorone diisocyanate, and the mixture was heated to 100 in a nitrogen stream.
Reaction for 6 hours at ℃ 2.60% free isocyanate content
A urethane prepolymer of was obtained.

Comparative Example 2 500 parts of the urethane prepolymer obtained in Comparative Example 1 was further added with a rosin ester (trade name: Super Ester S-115,
215.3 parts of pentaerythritol ester of disproportionated rosin, manufactured by Arakawa Chemical Industry Co., Ltd. was added and mixed by stirring at 100 ° C. for 1 hour to give a free isocyanate content of 1.75%.
A urethane prepolymer of was obtained. The rosin content in the resin solid content is 26.7%.

(Evaluation of Adhesiveness) The urethane prepolymers of Examples 1 to 3 and Comparative Examples 1 and 2 were used, and the coating amount was 20.
Corona discharge treated polypropylene (thickness: 0.3 mm) was attached to the tape so as to have g / m ² to prepare a test tape. Peel strength after leaving the test tape at room temperature for 30 minutes, and peel strength and heat resistant peel strength after leaving at room temperature for 10 days (humidity 60%) (environmental temperature 70 ° C., 1 kg load).
Was evaluated under the following conditions. The evaluation results are shown in Table 1. Peel strength: T-type peel strength at a pulling speed (100 mm / min). Heat-resistant peel strength: The number of days until the tape peels off by 1 mm.

[0043]

[Table 1]

Claims (4)

[Claims] 1. A polyurethane comprising a high-molecular polyol and a polyisocyanate compound as main constituents, wherein the high-molecular polyol comprises (1) a rosin obtained by reacting a glycidyl ester of a rosin and a polybasic acid. A polymer polyol having a monoglyceride skeleton, or (2) a polymer polyol having a monoglyceride skeleton of a rosin obtained by reacting a glycidyl ester of a rosin, a polybasic acid and a polyhydric alcohol. A polyurethane having a rosin skeleton. 2. The number average molecular weight of the polymer polyol having a monoglyceride skeleton of rosin is 500 to 10
The polyurethane having a rosin skeleton according to claim 1, which is 000. 3. The rosin content in the resin solid content of the polyurethane is 3 to 60% by weight.
A polyurethane having the rosin skeleton described. 4. A polyurethane adhesive comprising the polyurethane having a rosin skeleton according to claim 1.