TWI486418B - Breathable polyurethane adhesive - Google Patents

Description

Moisture permeable polyurethane adhesive

This invention relates to an adhesive, and more particularly to a polyurethane adhesive.

Polyurethane Adhesive refers to an adhesive containing a urethane group (-NHCOO-) or an isocyanate group (-NCO) in a molecular chain. Since the polyurethane molecule contains a highly polar functional group (NCO), , with materials containing active hydrogen, such as: wood, fabric, leather, metal, ceramics, rubber, etc. have strong chemical adhesion. In addition, since the polyurethane adhesive has the advantages of toughness controllability, simple bonding method, low temperature resistance, and good stability, the development of the polyurethane adhesive has been extremely rapid in recent years. Among them, the moisture-curable polyurethane adhesive is obtained by reacting a prepolymer having an isocyanate group with water and gas, crosslinking and curing to adhere, and having good adhesion to the adhered substrate, and thus has been widely used. Applied to different fields. It is the object of the inventor of the present invention to develop a polyurethane adhesive which is mainly polyurethane, has good adhesion strength with fabric, and can have high gas permeability/moisture permeability to provide more choices for those skilled in the art. One.

Generally used for the bonding of cloth and cloth in fabric or cloth to film surface, the molecular segment has a moisture-curing type of moisture permeable polymer. A urethane prepolymer, after repeated washing of the fabric, the adhesion strength between the fabric and the fabric is reduced, which may cause the cloth and cloth in the fabric, or the peeling or peeling between the cloth and the film surface. The situation arises. Therefore, how to improve the adhesion strength between the adhesive and the fabric to make it washable and breathable is a direction that technicians in the field are striving to develop.

Accordingly, it is an object of the present invention to provide a polyurethane adhesive having high moisture permeability and good adhesion to fabric.

Thus, the polyurethane adhesive of the present invention comprises a polyurethane comprising at least one side chain polyol as shown in formula (I) and at least one structure different from formula (I), a common polyol, and at least one The isocyanate is polymerized, wherein R ¹ and R ² are C ₁ -C ₅ alkylene groups, and R ³ is a hydrophilic polyether polyol functional structure, and the isocyanate and all polyol functional groups are equivalent. The ratio (NCO/OH) is between 1.5 and 2.5.

Preferably, R ¹ and R ² are an exoethyl, a propyl or a butyl group, and R ³ is a polyethylene glycol monomethyl ether.

Preferably, the molecular weight of R ³ is between 900 and 2,500.

Preferably, the polyol further comprises a polyester polyol, a polyether polyol, and a combination of the foregoing.

Preferably, the weight percentage of the polyol is 100% by weight. The weight percentage of the polyol represented by the formula (I) is from 7 to 10% by weight.

Preferably, the weight percentage of the polyol represented by the formula (I) is 9.5 wt% based on 100% by weight of the polyol.

Preferably, the polyester polyol comprises a crystalline polyester polyol and an amorphous polyester polyol, and the weight ratio of the amorphous and low crystalline polyester polyol to the crystalline polyester polyol Between 2~3.

Preferably, the polyurethane has a viscosity of 3,000 to 9000 cps, a moisture permeability of not less than 30,000 g/m ² /Day, and a peel strength of not less than 2.0 lb/in.

Preferably, the polyurethane has an isocyanate functional group content (NCO%) of from 2 to 5%.

Preferably, the diisocyanate is selected from the group consisting of diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, and a combination thereof.

The effect of the present invention lies in that the structural design of the polyol having a hydrophilic functional group in the side chain is cited, and a polyurethane adhesive having good adhesion, water washing resistance and high moisture permeability is obtained.

A preferred embodiment of the moisture-curable polyurethane adhesive of the present invention comprises a polyurethane having at least one of the following formula (I) a side chain having a hydrophilic polyether polyol structure side chain polyol, other at least one common polyol, and at least one diisocyanate polymerized, and the functional group equivalent ratio (NCO/OH) of the isocyanate and all polyols Between 1.5 and 2.5.

Wherein R ¹ and R ² are C ₁ -C ₅ alkylene groups, and R ³ is a hydrophilic polyether polyol structure. Preferably, R ¹ and R ² are an exoethyl, a propyl or a butyl group, and R ^{3 is} selected from a structure having a polyethylene glycol monomethyl ether (MPEG); more preferably, the R ¹ , R ^{2 is} selected from an extended ethyl group.

Specifically, the side chain polyol compound represented by the above formula (I) is prepared by reacting diisocyanate A with polyether alcohol B to obtain a urethane compound C, and then adding a diol amine compound D to carry out a reaction, that is, A short molecular chain diol (hereinafter referred to as SPEG) having a hydrophilic polyether polyol in a side chain can be obtained, and the reaction mechanism is as follows:

Preferably, the polyether alcohol B is selected from the group consisting of polyethylene glycol monomethyl ether (MPEG) having a molecular weight of 900 to 2500, and the glycol amine compound D is selected from the group consisting of Diethanol amine and 3-( (hydroxyethyl)amino)propanol (3-[(2-hydroxyethyl)amino]propan-1-ol or 4-((2-hydroxyethyl)amino)butanol (4-[(3-hydroxypropyl)amino) ]butan-1-ol).

It is to be noted that the polyol used for the polymerization may include, in addition to the short molecular chain diol as shown in the formula (I), other polyols which are different from the structure of the formula (I), such as: a crystalline polyester polyol, an amorphous polyester polyol, a polyether polyol, and in particular, the common polyols may be selected, for example, from polycarbonate polyols, polyethylene glycols, polytetramethylene glycols, Polypropylene glycol, or a mixture of these.

The present invention utilizes the polyol compound represented by the formula (I) as the polyol for polyurethane polymerization, and controls the moisture permeability of the polyurethane by the content of the hydrophilic polyether functional group in the side chain polyol of the formula (I). Sex and viscosity, the higher the content of the hydrophilic functional group, the higher the hydrophilicity, and the higher the moisture permeability of the polyurethane obtained after polymerization, but the excessively high content will increase the viscosity of the synthesized polyurethane, so that the viscosity of the processing is 100 ° C. If it is too high, the bonding effect is not good; on the contrary, the lower the content of the hydrophilic functional group, the lower the hydrophilicity, that is, the lower the moisture permeability of the polyurethane obtained after polymerization; however, PEG (ie, hydrophilic polyether functional group) If the molecular weight is too high, the washing resistance of the obtained adhesive is deteriorated. Therefore, the present invention utilizes the molecular weight of the polyether alcohol B to be between 900 and 2500, and is further coordinated with the side chain of the formula (I). The content of the polyol allows the adhesive to have both good moisture permeability and washing resistance.

In addition, the present invention can also utilize the addition of a non-crystalline or low-crystalline polyester polyol, and a polyether polyol to control the viscosity of the polyurethane; and the addition of the crystalline polyester polyol can further improve the obtained polyurethane. Heat resistance and strength.

Preferably, the weight percentage of the side chain polyol represented by the formula (I) is from 7 to 10% by weight, based on 100% by weight of the polyol for polymerization, more preferably, the formula (I) The weight percentage of the side chain polyol is 9.5 wt%, and the weight ratio of the amorphous and low crystalline polyester polyol to the crystalline polyester polyol is between 2 and 3.

The diisocyanate is selected from the group consisting of aromatic isomerates commonly used in the synthesis of polyurethanes, such as toluene diisocyanate (TDI), 4,4 diisocyanate diphenylmethane (MDI), hexamethylene diisocyanate ( HDI), or one of the foregoing combinations.

In addition, the polyurethane may further comprise a chain extender for increasing the molecular weight of the polymerization, and an antioxidant. The chain extender may be selected from the group consisting of ethylene glycol, 1,3-dihydroxypropane, and 1,4-dibutylpropane. 1,4-dihydroxy-butane, 1,6-dihydroxyhexane, Glycerol, trimethylolpropane (TMP), hydroquinone (Hydroquinone) Bis(2-hydroxyethoxy)benzene, HQEE), or a combination of the above, since the use of the chain extender and the antioxidant is a commonly used reagent in the synthesis of polyurethane, and is not the focus of the present invention, Features are no longer explained.

It should be further explained that since the viscosity of the polyurethane adhesive affects the coating property, the viscosity is too high or too low to obtain a uniform coating. Therefore, the viscosity of the polyurethane adhesive is preferably controlled at 3000~. 9000 cps, and in order to enhance the comfort of the fabric using the polyurethane adhesive, the polyurethane adhesive has a moisture permeability of more than 30,000 g/m ² /day.

The polyurethane adhesive of the present invention will be described in the following specific examples and comparative examples.

SPEG synthesis:

First, the polyethylene glycol monomethyl ether (MPEG) with a molecular weight of 1000 was first removed at 100 ° C under vacuum, and then the MPEG after water removal was added to a reaction tank with nitrogen gas to control the temperature at 50 ° C. Under the conditions, toluene diisocyanate was added to the reaction tank, and reacted at 80 ° C for 2 to 3 hours, and then the temperature of the reaction vessel was lowered to 50 ° C, and then diethanolamine (DEA) was added for 20 minutes to obtain a side chain. A short molecular chain diol of a hydrophilic polyether can be used to polymerize SPEG.

Specific example 1

First, a low crystalline polyester polyol having a total weight percentage of 53.1% by weight based on 100% by weight of the total polyol (product name: ARU2020, molecular weight: 2000, manufacturer: Yongpurer) 21.2% by weight of crystalline polyester polyol (product name: ARU2420, molecular weight: 2000, manufacturer: Yongpurer), 15.9% by weight of hydrophobic polyether polyol (name: PPG, molecular weight: 1000, manufacturer: Stable polymer chemistry), and 9.5 wt% of the previously synthesized SPEG added Mixing and stirring in a nitrogen reaction tank at a temperature maintained at 60 ° C, and then adding 3.1 wt% of toluene diisocyanate to the total weight of the reactants based on 100% by weight of the total reactants. TDI), 17.7 wt% of 4,4 diisocyanate diphenylmethane (MDI), 0.5 wt% of an alcohol antioxidant, and 0.3% of an alcohol chain extender are added to the above reaction tank at a temperature of 80 ° C The reaction was continued for 3 hours in the reaction tank, and then the reaction mixture was poured out to obtain a polyurethane adhesive having an NCO/OH ratio of 1.9 and a viscosity of 8500 cps at 100 ° C, and sealed and stored for use.

Specific example 2

The specific examples 2 to 3 are substantially the same as the production method of the specific example 1, and the difference lies in the type and amount of the polyol, and the polyurethane adhesive obtained in the specific example 2, wherein NCO/OH = 1.9, and the viscosity is 8000 cps (100 ° C).

Comparative example 1~4

The comparative examples 1 to 4 were substantially the same as the production method of the specific example 1, except that the types and amounts of the polyols of the comparative examples were different.

Next, the polyurethane adhesives prepared in the above Specific Examples 1 to 2 and Comparative Examples 1 to 4 were subjected to peel strength, moisture permeability, and water pressure resistance test.

Peel strength measurement:

The measurement was carried out by the ASTM D2724 test method.

1. Use a hot air blower to heat seal the water stop strip to the coating layer or the bonding layer. A sample (sample size: 3 pieces of 15*2.5 in warp and weft; unit: cm) was taken, and after 10 times of water washing, the interlaminar peel strength was measured by a tensile machine.

2. Firstly pull the fitting sample by 10cm, and let the cloth have 10cm left in the bonding place (or pull the sample to the middle of the test sample).

3. Clamp the cloth that has been pulled by hand to the upper and lower chucks of the tension machine.

4. Select the appropriate program and test to get the data.

Moisture permeability test:

The test was carried out using the JIS L1099 B1 test method (reverse cup method).

1. Place a solution of potassium acetate: distilled water = 3:1 in a test cup, and place it in an amount of about 1.5 cm (about 8 minutes) from the upper end of the cup edge of the test cup (round cup of 6 cm in diameter).

2. Fill a test tank with water to the mark, place the test tank in a constant temperature and humidity machine, set the temperature to 30±2°C, and the relative humidity is 65±5%. The circulating air in the standby station meets the temperature/humidity setting requirements. .

3. The cloth containing the 8.3 cm round test piece is wrapped with the front side facing up on the iron cup on the sink cover, and fastened with a rubber band so that the back side of the test cloth can be immersed together with the iron cup 1 cm below the water line of the sink.

4. Measure the weight (a1) of the test cup into which the medicament is placed by using a scale.

5. Pour the test cup into the iron cup on the sink cover, and make sure that the constant temperature and humidity machine has reached the set requirements, then cover the sink cover to cover the sink.

After 6.15min, take out the test cup and immediately measure the weight (a2) with the balance, and calculate the moisture permeability according to the formula.

Permeability = △g/A*△T

△g=a2-a1

△T=test time

A = area corresponding to the inner diameter of the test cup

Water pressure resistance measurement:

Measurement using the JIS L1092 test method

1. Using a high water pressure resistance (10000mm/min) tester, fill the water tank with high water pressure resistance and fill it with the iron rod to make the horizontal pressure uniform.

2. Cover the test piece with the test cloth (30x30cm) containing the adhesive face down, start the test, and start to appear on the surface. When the third drop of water appears, stop the test and record the test value.

The components and the amounts by weight of the specific examples 1 to 2 and the comparative examples 1 to 4 are summarized in Table 1.

It can be seen from Table 1 that the polyurethane adhesive obtained by polymerization when the SPEG content is 7 to 10 wt% not only has a good coating viscosity, but also has moisture permeability and maintains good adhesion strength, while SPEG is used. When the content is further controlled to 9.5 wt%, the polyurethane obtained by polymerization can maintain not only the same adhesive strength but also a better moisture permeability.

In summary, the present invention utilizes the structural design of the polyol, A short-chain chain diol having a hydrophilic polyether as shown in the above formula (I) and a polyurethane binder obtained by copolymerizing the polymerized monomer are not only preferably coated. The viscosity, and at the same time, can have high moisture permeability and can exhibit high adhesion strength to the fabric, so the object of the present invention can be achieved.

The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, that is, the simple equivalent changes and modifications made by the patent application scope and patent specification content of the present invention, All remain within the scope of the invention patent.

Claims (10)

A moisture-permeable polyurethane adhesive comprising a polyurethane which is cross-linked and polymerizable after absorbing moisture, and the polyurethane is obtained by polymerizing at least one polyol of the formula (I) and at least one diisocyanate. R ¹ and R ² are C ₁ -C ₅ alkylene groups, R ³ is a hydrophilic polyether polyol structure, and the functional group equivalent ratio (NCO/OH) of the isocyanate and the polyol is between 1.5~ 2.5. The moisture-permeable polyurethane adhesive according to claim 1, wherein R ¹ and R ² are an exoethyl group, a propyl group or a butyl group, and R ³ has a polyethylene glycol monomethyl ether structure. The moisture-permeable polyurethane adhesive according to claim 1, wherein the molecular weight of R ³ is from 900 to 2,500. The moisture-permeable polyurethane adhesive according to claim 1, wherein the polyol further comprises a polyester polyol, a polyether polyol, and a combination of the foregoing. The moisture-permeable polyurethane adhesive according to claim 4, wherein the weight percentage of the polyol represented by the formula (I) is from 7 to 10% by weight based on 100% by weight of the total polyol. The moisture-permeable polyurethane adhesive according to claim 5, wherein the formula (I) is more than 100% by weight based on the total weight of the polyol. The weight percentage of the alcohol was 9.5 wt%. The moisture-permeable polyurethane adhesive according to claim 4, wherein the polyester polyol comprises a crystalline polyester polyol, an amorphous polyester polyol, a low-crystalline polyester polyol, or a combination thereof And the weight ratio of the amorphous and low crystalline polyester polyol to the crystalline polyester polyol is between 2 and 3. The moisture-permeable polyurethane adhesive according to claim 1, wherein the polyurethane has a viscosity of from 3,000 to 9000 cps at 100 ° C, a moisture permeability of not less than 30,000 g/m ² /Day, and a peel strength of not less than 2.0 lb/in. . The moisture-permeable polyurethane adhesive according to claim 1, wherein the polyurethane has an isocyanate functional group content (NCO%) of 2 to 5%. The moisture-permeable polyurethane adhesive according to claim 1, wherein the diisocyanate is selected from the group consisting of diphenylmethane diisocyanate, methyl diisocyanate, and hexamethylene diisocyanate, one of which is a combination.