JPS60221415A - Aqueous dispersion of polyisocyanate - Google Patents

Abstract

PURPOSE:To provide the titled dispersion for adhesive, etc., having long pot-life, excellent workability and high adhesive strength, and containing a polyisocyanate in a uniformly dispersed state, by compounding water, a polyisocyanate, a nonionic surfactant and a specific diamine. CONSTITUTION:The objective dispersion can be produced by compounding (A) water, (B) a polyisocyanate having two or more isocyanate groups, (C) a nonionic surfactant and (D) a diamine of formula (n is >=19, preferably 19-451 on an average). The component D can be prepared by cyanoethylating a polyethylene glycol with acrylonitrile, and hydrogenating the product. The amounts of the components C and D are preferably 1.5-2.5pts.(wt.) and 1.2-5pts. per 100pts. of the component B, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aqueous polyisocyanate dispersion, and more particularly to an aqueous polyisocyanate dispersion in which polyisocyanate is uniformly dispersed and has a long pot life.

Conventionally, urea resin adhesives, melamine resin adhesives, phenol resin adhesives, and the like have been widely used as adhesives for manufacturing plywood, secondary processing of plywood, and manufacturing of particle board and laminated wood. However, these adhesives generate formaldehyde during use and processing,
Because formaldehyde remains on the plywood of products,
There were drawbacks such as pollution and sanitary hazards in the working environment and when using product plywood.

Polyisocyanate adhesives have been proposed as adhesives that can avoid the above-mentioned drawbacks of adhesives using formaldehyde and provide adhesion with excellent water resistance. For example, water-based adhesives in which polyisocyanate is blended with other hydrophilic organic solvents or surfactants have been proposed (see JP-A-49-22438 and JP-A-50-69134). Adhesives dispersed in solvents are difficult to uniformly apply to adherends and have poor adhesive strength because it is extremely difficult to uniformly disperse the polyisocyanate in an aqueous solvent. I couldn't get it.

In addition, in this type of polyisocyanate adhesive,
Although the use of self-emulsifying polyisocyanates has already been proposed (see Japanese Patent Publication No. 55-7472), polyisocyanate aqueous dispersions using such self-emulsifying polyisocyanates generally have a short pot life after emulsification. In a relatively short time, either the viscosity increased or the effective incyanate content decreased, with the result that insufficient adhesion was obtained.

An object of the present invention is to provide an aqueous polyisocyanate dispersion (adhesive, etc.) in which polyisocyanate is uniformly dispersed and which has a long usable life.

That is, the polyisocyanate aqueous dispersion of the present invention is
water, a polyisocyanate having two or more incyanate groups, a nonionic surfactant and a diamine of the general formula %, where n is an average value of at least 19. It is a dispersion characterized by the following.

The polyisocyanates used in the present invention include, for example, aliphatic polyisocyanates such as hexamethylene diisocyanate; m- and p-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-
Aromatic polyinsyanates such as tolylene diisocyanate, tolylene diisocyanate with a 2,4 unit/2,6 unit ratio of 80/20 to 65/35, diphenylmethane-4,4'-diisocyanate; bis-(incyanatecyclohexyl)methane etc.) 1
Examples include crude products of each of the above polyisocyanates, such as crude tolylene diisocyanate and crude diphenylmethane diisocyanate (also called polymethylene polyphenyl polyisocyanate).

One type of these polyisocyanates may be used, or two or more types may be used in combination.

The nonionic surfactant used in the present invention may be either a polyethylene glycol type or a polyhydric alcohol type, but includes higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, fatty acid ethylene oxide adducts, and polyhydric alcohols. Polyethylene glycol types such as fatty acid ester ethylene oxide adducts, higher alkylamine ethylene oxide adducts, fatty acid amide ethylene oxide adducts, ethylene oxide adducts of fats and oils, and polypropylene glycol ethylene oxide adducts are preferred.

Particularly preferred is polypropylene glycol ethylene oxide adduct. These ethylene oxide adducts are 1 (LB is preferably 3 to 15, 5 to 1
2 is the most preferable. Two or more types of nonionic surfactants may also be used in combination.

The diamine represented by the general formula (1) used in the present invention (hereinafter sometimes referred to as "diamine (I)") can be obtained by the usual method of hydrogenating polyethylene glycol cyanoethylated with acrylonitrile. can be easily manufactured by The diamine (I) has an average value of n in formula (1) of 19 or more (that is, an average molecular weight of about 1000 or more), but particularly preferably an average value of n of 90 or more. Above, 451 or less (average molecular weight 400
0 to 20,000). In addition, diamine (I
) is solid at room temperature when the average molecular weight is 700 or more, so it is convenient to dissolve it in a suitable solvent (for example, water, acetone, etc.) for storage, transportation, and use in the present invention.

The amount of diamine (1) in the present invention is 1 to 100 parts (parts by weight, the same applies hereinafter) of polyisocyanate.
10 parts, preferably 1.2 to 5 parts.

If the amount used is too small, sufficient dispersion of the polyisocyanate becomes difficult and the desired aqueous dispersion cannot be obtained.

On the other hand, if the amount of diamine (I) used is too large, the incyanate concentration will be relatively reduced, which will restrict the use of the aqueous dispersion, and the water absorption of the dispersion will become large, causing problems.

The amount of nonionic surfactant used in the present invention is 0.5 to 3 parts, preferably 1.5 to 2.5 parts, based on 100 parts of polyisocyanate. If the amount used is too small, the usable life of the aqueous polyisocyanate dispersion will be shortened, and if it is too large, the water absorption of the aqueous polyisocyanate dispersion will be high, resulting in restrictions on its uses.

To produce the polyisocyanate aqueous dispersion of the present invention, diamine (I) is usually dissolved in water to form a diamine aqueous solution, a nonionic surfactant is added to this, and the mixture is stirred at high speed. It is convenient to add polyisocyanate to this.

The aqueous polyisocyanate dispersion of the present invention exhibits less decrease in effective isocyanate group content than dispersions using conventional self-emulsifying polyisocyanates, so it has a long pot life, especially at relatively high temperatures. The time period will be extended. This is presumed to be because the added polyisocyanate immediately reacts with diamine (I) in the aqueous solution to produce a type of surfactant having a urea bond (-NHCONH-). That is, since diamine (I) and polyicanate are immediately bonded via a urea bond, the resulting product is formed by the oxyethylene group of the diamine acting as a hydrophilic group and the hydrocarbon group of the polyisocyanate acting as a lipophilic group. It is speculated that if a type of surfactant acts as a self-emulsifying polyisocyanate, the resulting aqueous dispersion will have less reduction in effective isocyanate group content and a longer pot life. It is believed that the nonionic surfactant blended at the same time acts to promote the dispersion of this self-emulsifying polyisocyanate.

As described above, the polyisocyanate aqueous dispersion of the present invention has a smaller reduction rate of effective incyanate groups and has a longer pot life than conventional aqueous dispersions using self-emulsifying polyinsyanate. It has excellent workability in coating, etc., and has a high effective isocyanate group content, so it has a large amount of isocyanate groups that work effectively in bonding processes, etc.
As a result, good adhesive strength is obtained.

The polyisocyanate aqueous dispersion of the present invention can be used as a water-based binder, water-based adhesive, etc. for bonding wood chips, polylyl tan foam, adhesion of wood, paper, cloth, etc., urethane 7-ohm scraps, urethane bumper scraps, etc. It can be widely and advantageously used for bonding elastomer debris such as.

Next, the present invention will be further explained in detail by giving Examples and Comparative Examples.

Example 1 Diamine (I) with an n value of about 133 (Yoken Fine Chemical Co., Ltd. trade name P B OAm1ne 6000, average molecular weight 6,114) 1.5 f, and a Pluronic type nonionic surfactant (Jiryu Kakogyo Co., Ltd.) Company product name, Pluronic L-64, average molecular weight 2,900, ML B 10
) 0.6? was placed in a polyethylene beaker with a capacity of fk3001Lt, 57.1-liters of water was added, and while stirring and mixing at 200 rpm using a stirrer supported by a turbine blade, polymethylene polyphenyl polyinsyanate (product name of Kasei Upjikin Co., Ltd.) was added. Papi 135,
NCO content a1. s%) 409- was added to obtain an aqueous polyisocyanate dispersion.

This dispersion could be redispersed even after being left at 40° C. for 80 minutes (61), and the residual rate of isocyanate groups (NCO) in the dispersion at that time was 95%.

This dispersion was applied by spraying to a chip for both the front and back layers with a water content of 8% (heavy weight, the same applies hereinafter) at a ratio of 7 inches to the absolute dry tip amount. Separately, this dispersion was applied by spraying to a core layer chip having a moisture content of 5 inches at a ratio of 4 inches to the amount of bone-dry chips.

After spraying the dispersion, forming was carried out so that the amount of chips in both the front and back layers and the core layer was 1+3:1 by weight, and the temperature was heated to 17.
Molding was carried out under the conditions of 0° C., hot pressing time of 4 minutes, and pressing pressure of 30 #f/d to obtain a molded boat having a board thickness of 13 cm, an average board density of o, and 7 t/ail.

This board was tested according to the method specified in JIS A-5908, and the results were as follows.

Normal bending strength 250k! g/ctA 2-hour boiling bending strength 150kg/cr1 Bending strength survival rate 60chi Peeling strength 12klil/c! t Example 2 Diamine (1) with n value of 90 (trade name of Toshi Co., Ltd.,
PGD-40, average molecular weight 4,114 > 2 P, and nonionic surfactant Pulminic L-62 (trade name of Mudenka Kogyo Co., Ltd., average molecular weight 2,500, HLB 6.3
) 0.5 F into a polyethylene beaker with a capacity of 300 d, 57.5 P of water was added, and while stirring and mixing under the same conditions as in Example 1, the same polymethylene polyphenyl polyisocyanate 40 as used in Example 1 was added.
9- was added to obtain a polyisocyanate aqueous dispersion.

This dispersion could be redispersed even after being left at 40° C. for 70 minutes, and the NCO residual rate at this time was 93.

Using this dispersion, the average board density was 0°7P/c! according to the method of Example 1! I got t board. The test results for this board were as follows.

Normal bending strength: 240 Yu/d Boiling 2-hour bending strength: 135 Yu/cit Bending strength remaining rate: 56 Example 3 Diamine (I) with an n value of 19 (trade name of Toshi Co., Ltd.)
PGD-10, average molecular weight 1,114) 2.5 P
, and 1.5 y- of the same nonionic surfactant used in Example 1 were placed in a polyethylene beaker with a capacity of 300 ml, and 56 ml of water was added. was added, and while stirring and mixing under the same conditions as in Example 1, the same polymethylene polyphenyl polyisocyanate (40Ii-) used in Example 1 was added to obtain an aqueous polyisocyanate dispersion.

This dispersion could be redispersed even after being left at 40° C. for 60 minutes, and the NCO residual rate at this time was 93.

Using this dispersion, the method of Example 1 was followed to obtain an average board density of 0. ．． I got a board of 7t/cr&. The test results for this board were as follows.

Normal bending strength: 220 to 9/crl 2-hour boiling bending strength: 150kg/c! 1 Flexural strength residual rate 61 Peel strength 11#/di Example 4 The same diamine 3P1 and the same nonionic surfactant 0.6? as used in Example 1. into a polyethylene beaker and add 56.4L of water. Add
Diphenylmethane diisocyanate (trade name, Kasei Upjohn Co., Ltd., 15ONATE 143L, NCO content = 29.0%) was added to this while stirring and mixing under the same conditions as in Example 1. was added to obtain a polyisocyanate dispersion.

This dispersion could be redispersed even after being left at 40° C. for 100 minutes, and the NCO residual rate at this time was 96%.

Using this dispersion, the average density was 0 according to the method of Example 1.
A board of ゜7y/al was obtained. The test results for this board were as follows.

Normal bending strength 260kg/cIIt 2-hour boiling bending strength xsskglcr & bending strength survival rate 60cm Peeling strength 12kliF/b Example 5 Same diamine as used in Example 1 3y-1 Same as used in Example 1 Pluronic type nonionic surfactant 0.3? , and Tetronic type nonionic surfactant (trade name of Mudenka Kogyo Co., Ltd., Tetronic TR-70)
2, average molecular weight 3,500, HL B6) 0.6i
into a polyethylene beaker with a capacity of 300 d, and add 57 ml of water. IP was added, and while stirring and mixing under the same conditions as in Example 1, 40 t of the same polymethylene polyphenyl polyisocyanate as used in Example 1 was added.
was added to obtain a polyisocyanate aqueous dispersion.

This dispersion could be redispersed even after being left at 40° C. for 120 minutes, and the NCO residual rate at that time was 97.

Using this dispersion, the average density o was obtained according to the method of Example 1.
, an rfP/cd board was obtained. The test results for this board were as follows.

Normal bending strength: 250 to 9/cr/l Bending strength after boiling for 2 hours! 50kg/c/L bending strength residual rate 60cm peel strength 13 kg/cIl Example 6 Polyethylene glycol (average molecular weight approximately 10,000)
is dicyanoethylated by a conventional method, and then hydrogenated,
A diamine having an average molecular weight of about 10,100 was obtained [this diamine was a diamine in which the value of n in general formula (1) was about 226].

This diamine 5? , and the same nonionic surfactant 2.5Fi used in Example 1, in a volume J1300-
into a polyethylene beaker, add 52.59 g of water, and while stirring and mixing under the same conditions as in Example 1, add 40 fP of the same polymethylene polyphenyl polyisocyanate used in Example 1, A polyisocyanate aqueous dispersion was obtained.

This dispersion can be redispersed even after being left at 40°C for 120 minutes, and the NCO residual rate at this time is 97%.
.

Using this dispersion, the average density was 0 according to the method of Example 1.
．． I got a 7y/cIi board. The test results for this board were as follows.

Normal bending strength 240kg/cI! 2-hour boiling bending strength 150 klil/d Bending strength remaining rate 62 cm Peeling strength 11 / CI Agent 1?
into a polyethylene beaker with a capacity of 300 d, and add 58 ml of water. While stirring and mixing under the same conditions as in Example 1, the same polymethylene polyphenyl polyisocyanate 40i as used in Example 1 was added thereto to obtain an aqueous polyisocyanate dispersion.

This dispersion could be redispersed even after being left at 40° C. for 70 minutes, and the NCO residual rate at this time was 94.

Using this dispersion, the average density o was obtained according to the method of Example 1.
, ty-/cd boards were obtained. The test results for this board were as follows.

Normal bending strength 240 kg/cr/2 hours after boiling Bending strength 145 to 9/c IIL bending strength survival rate 60% Peeling strength 11 Yu/d Example 8 The same diamine 2? as used in Example 1. , and polyethylene glycol ether type nonionic surfactant N
P-5 (Nikko Chemicals product name, HLB=8) 2y-
into a polyethylene beaker with a capacity of 300 ml, and add 69 ml of water. 27? was added to this while stirring and mixing under the same conditions as in Example 1. TDI80 [Kasei Upjohn Co., Ltd. trade name, 2.4- and 2.6-) lylene diisocyanate mixture (mixing ratio 80+20), NCO content = 4
7] was added to obtain an aqueous polyisocyanate dispersion.

This dispersion could be redispersed even after being left at 40° C. for 100 minutes, and the NCO residual rate at this time was 95.

Using this dispersion, the average density was 0 according to the method of Example 1.
．． I got a board of 7P/ffl. The test results for this board were as follows.

Normal bending strength: 265 Yu/cI Boiling 2-hour bending strength: 1501φ/cI1 Bending strength remaining rate: 57 Chi Peeling strength: 12KgI/cI! Example 9 The same diamine 2 as used in Example 2? , and polyethylene glycol type nonionic surfactant H8-20
45 (product name of NOF Corporation, polyoxyethylene octylphenyl ether, HL B =9.8) 2y-,
Pour into a polyethylene beaker with a capacity of 41,300 uJ.
56 g of water was added, and while stirring and mixing under the same conditions as in Example 1, the same polymethylene polyphenyl polyisocyanate 40P used in Example 1 was added.
was added to obtain a polyisocyanate aqueous dispersion.

This dispersion could be redispersed even after being left at 40° C. for 110 minutes, and the NCO residual rate at this time was 96%.

100% of rigid polyurethane foam waste for this dispersion 2051'? ,Wed 30? Mix and put into a mold and heat at 20℃
Compression for 1 hour was repeated three times. The obtained recycled foam block was taken out from the mold and its physical properties were tested, and the results were as follows.

Density 77 Yu/M” Compressive strength 10 inches compression 55 Yu/cr 125% compression 15
5kg1cr & Comparative Example 1 Diamine (trade name of Toshi Co., Ltd., PGD4, average molecular weight 514) 2P in which n in general formula (1) has a value of about 9, and the same nonionic surfactant 2y- as used in Example 2. into a polyethylene beaker with a capacity of 300 m/cm, add 50 i of water, and add 40 g of the same polymethylene polyphenyl polyisocyanate used in Example 1 while stirring and mixing under the same conditions as in Example 1. ? was added to obtain a polyisocyanate aqueous dispersion.

This dispersion cures immediately at 40°C and at 25°C.
Although redispersion was possible for up to 30 minutes at ℃, spraying could not be applied due to the high viscosity.

Comparative Example 2 Diethylene glycol monomethyl ether 219? , and potassium hydroxide (4.459 kg) were placed in an autoclave, and after purging with nitrogen gas, the temperature was raised to 90° C., and ethylene oxide 1686 F was added to react under pressure. The product was neutralized with a theoretical amount of phosphoric acid and filtered to give a product with a hydroxyl value of 53.

30 g of this product was charged into a reaction vessel, and under a nitrogen stream,
The same polymethylene polyphenyl polyisocyanate 1000 as used in Example 1 at room temperature. was charged and mixed, the internal temperature of the reaction vessel was raised to 80'C, and the mixture was stirred at 80°C for 2 hours.

The resulting product has a viscosity of 200 cps (25°C)
, the NCO content was 29%.

This product 409- was placed in a polyethylene beaker with a capacity of 300 WLt, and stirred and mixed under the same conditions as in Example 1; 60 fi' of water was added all at once to obtain an aqueous dispersion.

This dispersion could be redispersed at 40° C. for up to 30 minutes, but could not be redispersed after that.

Claims (1)

[Claims] l) water, a polyisocyanate having two or more isocyanate groups, a nonionic surfactant and the general formula % (wherein n represents a number of at least 19 on average); An aqueous polyisocyanate dispersion comprising the diamine shown below. 2) The average value of n in the general formula of diamine is 19 to 45
1. The aqueous polyisocyanate dispersion according to claim 1, which is