JP2002060456A - Urethane oligomer and pressure-sensitive adhesive base material containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a urethane oligomer which is used as a curative component for pressure-sensitive adhesive which does not contain an organic solvent, is hardly skin-irritative, and is excellent in moisture permeability. SOLUTION: This urethane oligomer is represented by formula [I]: A-I- P- I)r-(B-I)s}t-M (wherein A is a dehydrogenated residue of a hydroxyalkyl (meth) acrylate; I is an organic-diisocyanate-derived dicarbamoyl group; P is a dehydrogenated residue of a random copolymer formed from propylene oxide and 50-95% ethylene oxide and having a number average mol.wt. of 500-5,000; B is a dehydrogenated residue of a carboxyl-group-containing polyol compound; M is a dehydrogenated residue of a monool; when (t) is 1, then (r) is 1-20 and (s) is 0-20; and when (t) is 2-15, then (r) and (s) of the repeating unit (P-I)r-(B-I)s at both the ends of repeating units are each 0 or 1 and (r) and (s) of the repeating unit at other than the ends of repeating units are each 1-15).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a urethane oligomer used as a curing component of a base for a medical adhesive or a conductive resin-containing adhesive which directly touches the skin, and a pressure-sensitive adhesive base containing the same. It is about.

[0002]

2. Description of the Related Art An external preparation such as a poultice or a plaster has an adhesive applied to a base cloth so as to stick it to the skin. In addition, when performing an electroencephalogram measurement, an electrocardiographic measurement, or the like, a base agent containing a conductive resin is used to keep the electrode in close contact with the skin.

[0003] Acrylic polymers are widely used as base materials for pressure-sensitive adhesives and conductive resins used in such medical treatments. For example, when attaching an acrylic polymer to the base cloth, the acrylic polymer alone is too viscous to be applied to the base cloth, so it is difficult to apply the acrylic polymer synthesized using an organic solvent to a volatile solvent. After dissolving in an organic solvent and applying, the organic solvent is volatilized to exhibit adhesiveness. However, the organic solvent cannot completely evaporate and remains.

[0004] When the skin comes in contact with an adhesive or the like, it may be irritated by the remaining organic solvent, resulting in rash or itch. In addition, the organic solvent used in the production of the acrylic polymer or the organic solvent volatilized after coating on the base fabric must be recovered, which is complicated, environmental pollution and work safety. Is also a problem.

As a cured polymer obtained without using an organic solvent, European Patent Publication EP 0 305 175 A1 discloses a urethane resin using a polyol obtained by block copolymerizing ethylene oxide and polypropylene glycol. This is about 1000g ^/ m 2 · 24hr. It has moisture permeability.

However, there has been a demand for a novel hardening component for obtaining a hardened polymer having even better moisture permeability and containing no solvent and having low skin irritation.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and comprises urethane which is used as a hardening component such as a pressure-sensitive adhesive which contains no organic solvent, has low skin irritation and excellent moisture permeability. An object of the present invention is to provide an oligomer and a substrate for a pressure-sensitive adhesive containing the oligomer.

[0008]

The urethane oligomer of the present invention made to achieve the above object has the following formula [I] AI-{(PI) _r- (BI) _s } _t -M ... [I] (In the formula [I], A- is a dehydrogenated residue of hydroxyalkyl (meth) acrylate: -I- is a dicarbamoyl group derived from an organic diisocyanate: -P- is propylene Dehydrogenated residue of random copolymer of oxide and content ratio of 50 to 95% ethylene oxide having number average molecular weight of 500 to 5000: -B- is dehydrogenated residue of carboxyl group-containing polyol compound: -M is dehydration of monool Elementary residue: When t = 1, r is a number from 1 to 20 and s is a number from 0 to 20,
When t = 2 to 15, repeating unit (PI) _r- (B-
I) _s is represented by r, s = 0 to 1 at both ends of the repetition and r, s = 1 to 15 at other ends.

-I- is a linear aliphatic diisocyanate exemplified by hexamethylene diisocyanate and trimethylhexamethylene diisocyanate; isophorone diisocyanate, norbornane diisocyanate, hydrogenated xylylene diisocyanate, water Cycloaliphatic diisocyanates exemplified by charged diphenylmethane diisocyanates;
It is a dicarbamoyl group derived from at least one kind of organic diisocyanate compound selected from aromatic diisocyanates exemplified by tolylene diisocyanate, xylylene diisocyanate and diphenylmethane diisocyanate. Both of these two carbamoyl groups are A
A hydroxyalkyl (meth) acrylate constituting -P-, a random copolymer constituting -P-, a carboxy group-containing polyol compound constituting -B-, a hydroxyl group of a monol constituting -M, It is formed by the reaction of two isocyanate groups of an isocyanate compound.

As the random copolymer of ethylene oxide and propylene oxide constituting -P-, for example, those having an ethylene oxide ratio of 80%, 75%, or 60% are used. When a random copolymer of ethylene oxide and propylene oxide is used, the moisture permeability when the urethane oligomer is cured by cross-linking is remarkably superior to the case where a block copolymer thereof is used.

-B- is a monocarboxylic acid substituted with a hydroxyl group-containing group exemplified by 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, and 2,2-dimethylolvaleric acid; Dioxyadipic acid, dioxymaleic acid, dicarboxylic acid substituted with a group containing a hydroxyl group exemplified by tartaric acid, 2,6-dioxybenzoic acid exemplified by benzoic acid substituted by a hydroxyl group exemplified by 1,2- It is a dehydrogenated residue of a carboxyl group-containing polyol selected from dioxyglyceric acid. When the urethane oligomer contains this carboxyl group, when the urethane oligomer is cured by crosslinking, in addition to crosslinking by chemical covalent bonding due to polymerization of (meth) acryloyl groups, the urethane oligomer has another carboxyl group. As a result of forming a crosslink by an electrostatic hydrogen bond with a functional group of the oligomer, a hydrogel having a high swelling ratio is formed, and further excellent adhesive properties are exhibited.

-M is a dehydrogenated residue of a monol compound selected from alkoxy polyethylene glycol, alkoxy polypropylene glycol, aliphatic alcohol, hydroxyl group-containing (meth) acrylate, and carboxyl group-containing monoalcohol.

The number average molecular weight of the urethane oligomer is from 1 × 10 ^{3 to} 5 × 10 ⁵ .

The urethane oligomer can be used as a hardening component of a base material of a pressure-sensitive adhesive containing a medical pressure-sensitive adhesive or a conductive resin that directly touches the skin.

A method for producing this urethane oligomer will be described. The raw materials used are as follows.

The hydroxyalkyl (meth) acrylate for constituting A- in the above formula [I] is, for example, CH ₂ CRCR
¹ CO ₂ (CH ₂ ) _p OH, wherein R ¹ is a hydrogen group or a methyl group, and p is an integer of 2 to 4 is used. In this case A- is ^{_{CH 2 = CR 1 CO 2 (}} CH 2) a _p O-.

An organic diisocyanate for constituting -I-
Anatate compounds are, for example, (OCN) -R ²-(NCO),-
R²-The chain aliphatic diisocyanate, cycloaliphatic diisocyanate
Dehydration of cyanate and aromatic diisocyanate
What is used as a residue is used. At this time, -I- is -CON
H-R²It is a dicarbamoyl group represented by -NHCO-.

Random weights for constructing -P-
The coalescence is, for example, H- (OCHR³CHR⁴)_qWhat is indicated by O-H
Used. This random copolymer is represented by R³And R⁴Small
At least one hydrogen and the other hydrogen and methyl
Each repeating unit (OCHR³CHR ⁴) Is R³And R⁴And hydrogen
With a repeating unit content of 50 to 95%.
Q is the number average molecular weight of the copolymer
It is a number to be set to 00 to 5000. At this time -P-
Is-(OCHR³CHR⁴)_qIndicated by O-.

Similarly, the carboxyl group-containing polyol constituting -B- is represented by HOR ⁵ (CO ₂ H) -OH, and the above-mentioned substituted aliphatic monocarboxylic acid, substituted aliphatic dicarboxylic acid and substituted benzoic acid are used. . At this time, -B- is -OR ⁵
It is represented by (CO ₂ H) -O-.

Monool compound also constituting -M
Is, for example, H-O (CH₂CH₂-O)_v-R⁷Indicated by -R⁷To -CH₃
And the number of meth is such that v is a number average molecular weight of 200 to 1,000.
Alkoxypoxy exemplified by xylene polyethylene glycol
Ethylene glycol, H-O {CH ₂CH (CH₃) -O}_w-R⁸so
Indicated -R⁸To -CH₃And w is the number average molecular weight of 200 to 10.
For example, methoxypolypropylene glycol with the number of 00
The indicated alkoxy polypropylene glycol, H-O- (C
H₂)_xA linear aliphatic alcohol represented by H, wherein x is 1 to 30;
, H-O- (CH₂)_y-OCO-CR⁹= CH₂Indicated by R⁹The hydrogen
A hydroxyl group, wherein y is an integer of 2 to 4
Yes (meth) acrylate or H-O-R¹⁰(CO₂H)
Carboxyl group-containing monoalcohol is used
You. At this time, -M is -O (CH₂CH₂-O)_v-R⁷, -O {CH₂CH
(CH₃) -O}_w-R⁸, -O- (CH₂)_xH, -O- (CH₂)_y-OCO-CR
⁹= CH₂, Or -O-R¹⁰(CO₂H).

A urethane oligomer is produced using these raw materials. First, this random copolymer H- (OCHR ³ CHR
⁴⁾ _q OH, organic diisocyanate compound (OCN) -R 2 ^- (N
(CO). At this time, no catalyst may be used, but it is preferable to heat and stir at room temperature to 100 ° C in the presence of an organic metal catalyst or a basic catalyst. The catalyst includes cobalt naphthenate, zinc naphthenate, stannous chloride, stannic chloride,
Tetra-n-butyltin, tri-n-butyltin acetate, n-butyltin trichloride, trimethyltin hydroxide, dimethyltin dichloride, dibutyltin acetate, dibutyltin dilaurate, tin octenoate, trimethylamine, triethylamine, tributylamine, Dimethylbenzylamine. More preferably, in the presence of dibutyltin dilaurate, 80 to 100C
And heat with stirring. Then, polyaddition is carried out to form an adduct having isocyanate groups at both ends as shown in the following chemical reaction formula [II].

[0022]

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Next, a carboxyl group-containing polyol HOR ⁵ (CO ₂ H) -OH and an organic diisocyanate compound (OCN) -R ^2- (NCO) are added to the adduct, and polyaddition is performed under the same conditions. Let react. Then, the isocyanate group at the terminal undergoes an addition reaction with the carboxyl group-containing polyol, and the organic diisocyanate undergoes an addition reaction, and is sequentially repeated, thereby forming an adduct having a further extended main chain. The following formula [III] shows an example of an adduct extended to one terminal isocyanate group.

[0024]

Embedded image

In addition to the adduct obtained by the formula [III], a hydroxyalkyl (meth) acrylate compound CH ₂ CRCR
¹ CO ₂ (CH ₂ ) _p OH and a monol compound such as HO- (CH
₂ ) _x- OCO-CR ⁹ = CH ₂ was added, and the mixture was heated and stirred at 55 to 90 ° C. in the presence of p-methoxyphenol and di-t-butyl-hydroxytoluene to give the following reaction formula [IV]
Is obtained.

[0026]

Embedded image

The obtained urethane oligomer is an example of the one represented by the above formula [I]. This urethane oligomer is a viscous liquid and can be applied to a base fabric or the like without adding a solvent.

Incidentally, the random copolymer, the carboxyl group-containing polyol and the organic diisocyanate compound may be simultaneously mixed and subjected to a polyaddition reaction. The adhesive base of the present invention contains the urethane oligomer described above.

The cured polymer of the present invention is characterized in that the urethane oligomer is crosslinked by active energy. Since the urethane oligomer has high reactivity, it is rapidly crosslinked and cured when activated energy is applied. As a method for giving the active energy, for example, irradiation with ultraviolet rays or electron beams can be mentioned.

The cured polymer is obtained by adding a polymerization initiator to a urethane oligomer, applying the polymerization initiator to a base fabric such as a plastic film or cloth, and irradiating the base material with ultraviolet rays to cross-link unsaturated groups of a plurality of urethane oligomers. By this, it is manufactured.

The polymerization initiator is hydroxycyclohexyl phenyl ketone, 1-phenyl-2-hydroxy-2-methylpropan-1-one, 2,2-dimethoxy-2-phenylacetophenone, benzophenone, 2-methyl [4
-(Methylthio) phenyl] -2-morpholino-1-propanone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl)
-2-hydroxy-2-methylpropan-1-one, 4
-(2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 4- (2-acryloyloxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 4- (2-methacryloyloxyethoxy) )
Phenyl- (2-hydroxy-2-propyl) ketone,
At least one photoradical polymerization initiator selected from 2,4,6, -trimethylbenzoyldiphenylphosphine oxide, or dilauroloyl peroxide, dibutyl peroxide, dicumyl peroxide, t-butylcumyl peroxide , Α, α-bis
It is preferably at least one kind of thermal polymerization initiator selected from (t-butylperoxy-m-isopropyl) benzoate and 2,5-dimethyl-2,5-di (t-butylperoxy) hexane. .

This cured polymer has excellent tackiness. Furthermore, since it does not contain an organic solvent, it is skin-irritating. Since this polymer has high moisture permeability and forms a hydrogel by swelling with water, it can be suitably used as a medical adhesive or an adhesive containing a conductive resin.

The cured polymer can also be produced by applying a urethane oligomer to a base fabric such as a plastic film or cloth, and irradiating the base material with an electron beam to crosslink the urethane oligomer. In this case, since no polymerization initiator is required, the resulting polymer has further reduced skin irritation.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail. Hereinafter, Examples 1 and 2 show examples of trial production of a urethane oligomer to which the present invention is applied, and Example 3 shows an example of trial production of a cured polymer by polymerizing this oligomer.

Example 1 A polyether polyol (having a hydroxyl value of 56.1 and a molecular weight of 2) obtained by randomly copolymerizing ethylene oxide and propylene oxide at a ratio of 4: 1.
000) 526 g, dimethylolbutanoic acid 6 g, isophorone diisocyanate 76 g, antioxidant di-t-
0.1 g of butylhydroxyphenol was added to a 1-liter four-necked flask equipped with a stirrer, a condenser, and a thermometer, reacted at 100 ° C. for 4 hours, and then cooled to 80 ° C.
Then 5 g of 2-hydroxyethyl acrylate and 12 g
13 g of -hydroxystearic acid and 0.1 g of a polymerization inhibitor p-methoxyphenol were added and reacted at 85 ° C for 8 hours. The end of the reaction was confirmed by the disappearance of the isocyanate group (2280 cm ^-1 ) in the infrared absorption spectrum,
A urethane oligomer was obtained. The number average molecular weight of the obtained urethane oligomer was determined by gel permeation chromatography (GPC-1 manufactured by Showa Denko KK) using a value in terms of polystyrene, which was 2.0 × 10 ^4.
Met.

Example 2 A polyether polyol obtained by random copolymerizing ethylene oxide and propylene oxide at a ratio of 4: 1 (having a hydroxyl value of 56.1 and a molecular weight of 2)
000) 485 g, dimethylolbutanoic acid 27 g, isophorone diisocyanate 107 g, antioxidant di-
0.1 g of t-butylhydroxyphenol was added to a 1-liter four-necked flask equipped with a stirrer, a condenser, and a thermometer, reacted at 100 ° C. for 4 hours, and then cooled to 80 ° C. Then, 7 g of 2-hydroxyethyl acrylate,
Methoxy polyethylene glycol (molecular weight 400) 24
g and 0.1 g of a polymerization inhibitor p-methoxyphenol were added and reacted at 85 ° C. for 8 hours. The completion of the reaction was confirmed by the disappearance of the isocyanate group (2280 cm ^-1 ) in the infrared absorption spectrum, and a urethane oligomer was obtained. The number average molecular weight of the obtained urethane oligomer was determined by gel permeation chromatography (manufactured by Showa Denko KK:
It was 1.7 × 10 ^{4 as} determined by GPC-1) as a value in terms of polystyrene.

Example 3 98.5 g of the urethane oligomer obtained in Example 1 was used as a photoradical polymerization initiator.
1.5 g of-(2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone was added and mixed well.

Next, a urethane oligomer film is formed. At the time of preparation, a film having a thickness of 30 μm was formed on a polyethylene terephthalate (PET) film subjected to a release treatment.
m was coated with a urethane oligomer, and a release-treated PET film was placed on the urethane oligomer. This is 6m
Per minute on a conveyor moving at 10 cm / min.
Irradiation of 360 mJ of ultraviolet light with a kw high-pressure mercury lamp resulted in a film-shaped cured polymer.

The cured product has an adhesive strength of 0.7 kgf / in.
ch. The moisture permeability of this cured product is JIS Z 0
Approximately 2500 g / m ^2.
24 hr. And was excellent.

[0040]

As described above, since the urethane oligomer of the present invention is a viscous liquid, it can be applied to a base fabric as it is. A pressure-sensitive adhesive base material containing a urethane oligomer can be applied to the base fabric. At the time of such coating, there is no need to add an organic solvent or the like, so there is no environmental pollution due to evaporation of the solvent, and no solvent recovery equipment is required, which is safe. It can be used as a curing component for medical adhesives or conductive resin-containing bases that directly touch the skin.

After coating, the cured polymer of the urethane oligomer polymerized has excellent tackiness and is hypoallergenic to the skin. Since this polymer has high moisture permeability and forms a hydrogel by swelling with water,
It can be used as a medical adhesive or a conductive resin-containing base. Since the curing reaction speed is high, the manufacturing process can be shortened and simplified.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4C081 AA03 BA17 BB01 BB04 CA211 CC02 DA02 4J011 QB24 SA01 SA21 SA76 UA01 WA06 4J027 AG03 AG09 AG23 AG24 CB10 CC03 CD07 4J034 AA08 CA04 CA22 CB01 CC03 CC09 DB04 DF01 DF01 DF01 DF01 DF01 DF01 DF01 DF01 DF01 DF01 DF01 DF01 DF01 DF01 DF01 DF01 DF01 DG10 DH02 DH07 FA02 HA07 HC03 HC12 HC17 HC18 HC22 HC46 HC52 HC54 HC61 HC64 HC71 HC73 KB04 QB11 RA02 SD08 4J040 EF351 GA07 JB07 LA11 MA10 MA16 MB03 NA02 NA19

Claims (6)

[Claims] 1. A following formula [I] A-I - {(P- I) r - (B-I) s} t -M in ... [I] (formula [I], A- hydroxyalkyl Dehydrogenated residue of (meth) acrylate: -I- is a dicarbamoyl group derived from an organic diisocyanate: -P- is a random copolymer having a number average molecular weight of 500 to 5000 of propylene oxide and 50 to 95% ethylene oxide. -B- is a dehydrogenated residue of a carboxyl group-containing polyol compound: -M is a dehydrogenated residue of a monool: When t = 1, r is a number of 1 to 20 and s is 0 to 0 20 numbers,
When t = 2 to 15, repeating unit (PI) _r- (B-
_{I) s} is r at both ends of the repetition, s = 0 to 1 and r other than the both ends, s = 1 to 15) Urethane oligomer, characterized in that indicated by. 2. -I- is hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, norbornane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, tolylene diisocyanate. The urethane oligomer represented by the above formula [I], which is a dicarbamoyl group derived from at least one kind of organic diisocyanate compound selected from isocyanate, xylylene diisocyanate, and diphenylmethane diisocyanate. 3. The -B- is 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, 2,2-
Dimethylolvaleric acid, dioxyadipic acid, dioxymaleic acid, tartaric acid, 2,6-dioxybenzoic acid, 1,2
-A urethane oligomer represented by the above formula [I], which is a dehydrogenated residue of a carboxyl group-containing polyol selected from dioxyglyceric acid. 4. The method according to claim 1, wherein -M is a dehydrogenated residue of a monol compound selected from alkoxy polyethylene glycol, alkoxy polypropylene glycol, aliphatic alcohol, hydroxyl group-containing (meth) acrylate, and carboxyl group-containing monoalcohol. The urethane oligomer shown in [I] above. 5. A pressure-sensitive adhesive base comprising the urethane oligomer according to claim 1. 6. A cured polymer, wherein the urethane oligomer according to claim 1 is cross-linked by active energy.