JPH03146514A - Aqueous composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition, composed of a specific carboxylate group-containing blocked polyurethane, polyfunctional compound and water, efficiently reactive to provided a tough resin excellent in heat resistance through the composition is stable with a long pot life. CONSTITUTION:The objective composition consisting essentially of (A) a carboxylate group-containing blocked polyurethane prepared by reacting (i) a carboxylic acid (salt) group-containing polyoxyalkylene polyol, containing >=50wt.% oxyethylene groups and having groups COOX (X is H or cation) in the terminal parts of the backbone chain with (ii) a polyisocyanate having NCO in an amount so as to provide excessive equiv. based on OH of the compo nent (i) and (iii) a blocking agent in an amount corresponding to the excess equiv. of the component (ii) and converting the group X into cation if the group X is H, (B) a polyfunctional compound in an equiv. amount of 0.01-1 based on regenerated NCO in the component (A) and (C) water.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to aqueous compositions containing reactive polyurethanes.

[Conventional technology]

Urethane resin has a high affinity and adhesive strength for a wide variety of base materials such as fibers, paper, wood, and plastics, so urethane resin aqueous liquids can be used as fiber processing agents, paper processing agents, and adhesives for resins and films. Widely used. However, the so-called aqueous polyurethane liquid, whose reaction has been completed during the production of the aqueous liquid, has poor permeability and may not be able to penetrate between (inside) the base materials sufficiently, or it has already lost its reactivity, so covalent bonds are formed. It often happens that the strong adhesion created by the formation cannot be achieved. On the other hand, reactive urethane aqueous liquids containing so-called blocked incyanates retain their fluidity and viscosity even after the water has evaporated, so they can be used against relatively hydrophobic substrates. It can also be cast or infiltrated and bonded.

In addition, due to the high reactivity of isocyanate regenerated by heating etc., it has characteristics such as being able to form a strong bond with the substrate, and is therefore used in several applications.

[Problems to be Solved by the Invention] However, the conventional blocked incyanate compounds that have a pot life that can withstand normal use have insufficient heat curing properties and cannot be cured under high temperature and/or long time curing conditions. It is necessary and undesirable for the process. Furthermore, when curing properties are improved by adding a catalyst immediately before use, many inconvenient problems arise, such as the complexity of blending and stirring, the toxicity of heavy metal compounds such as tin and lead, and problems with post-treatment. The current situation is that

In addition, since the curing method is generally moisture curing, it is easily affected by humidity at high temperatures as mentioned above, and a long period of aging is required to complete the resin formation. . There have also been attempts to eliminate the above drawbacks by intentionally introducing water vapor at high temperatures (~100° C. or higher), but this is not preferable from a process standpoint.

Furthermore, in the case of moisture curing, it is impossible for resin formation to proceed ideally, and the polymer is a so-called oligomer whose ends are partially capped with amine, making it difficult to form a highly cross-linked polymer. It has drawbacks such as not being able to exhibit sufficient performance in terms of resin toughness, heat resistance, etc.

[Means to solve problems]

The present invention is the following invention made to solve the above-mentioned problems.

A carboxylic acid (salt) group-containing polyoxyalkylene polyol containing 50% by weight or more of oxyethylene groups and having a -COOX group (X: hydrogen atom or cation) at the end of the main chain, with an excess equivalent amount relative to the hydroxyl group of the polyol. A reaction product of a polyisocyanate having a proportion of incyanate groups and a blocking agent in an amount corresponding to the excess equivalent of the polyisocyanate, and when A carboxylic acid group-containing blocked polyurethane obtained by converting into
．． An aqueous composition containing a polyfunctional compound of 0.01 to 1.0 times the equivalent and water as essential components.

First, each raw material component in the present invention will be explained.

(1) Polyoxyalkylene polyol before carboxylic acid (salt) group introduction The polyoxyalkylene polyol in the present invention is a polyoxyalkylene polyol obtained by mixing or sequentially reacting ethylene oxide or ethylene oxide with another alkylene oxide as an initiator. It is a polyol. It may also be a mixture of two or more types of polyoxyalkylene polyols, and the initiator has a valence of 2 or more, especially 2 or more.
-A compound having a hydrogen atom (a hydrogen atom of a hydroxyl group or an amino group) with which an octavalent alkylene oxide can react, preferably one or more trivalent to tetravalent initiators or a mixture thereof with a divalent or pentavalent or higher valent initiator. It is. Polyhydric alcohols are particularly preferred as initiators; polyoxyalkylene polyols may be a mixture with other high molecular weight polyols that do not contain oxyethylene groups or have a small proportion thereof. Other high molecular weight polyols include polyoxyalkylene polyols containing few oxyethylene groups, polyether ester polyols containing a small number of ester groups, polycarbonate polyols, and polyoxytetramethylene polyols.

The polyoxyalkylene polyol in the present invention needs to have the following requirements on average.

Average oxyethylene group content: 50% by weight or more is required.

Preferably 60 to 95 weight % by weight, especially 70-90% by weight. follow and preferably an oxyethylene group. In addition, small amounts of other oxyalkylenes group, preferably oxypropylene Contains an ion group. oxyethylene base If the amount is small, the pH of the composition of the present invention may change. The stability against deterioration decreases.

It is preferable that the average number of hydroxyl groups exceeds 2. More preferably, the number of hydroxyl groups is 2.3 to 8, particularly 2.6 to 4. If the number of hydroxyl groups is small, the curing properties and adhesive properties of the polyurethane will deteriorate.

Average molecular weight per hydroxyl group: preferably from 200 to 4,000. Preferably, if the molecular weight is low, from 300 to 3,000 degrees, the cured polyurethane will be hard and brittle, and will not have any toughness. If a high molecular weight material is used, the permeability and adhesiveness of the blocked polyurethane will be insufficient.

(2) -CO to the polyoxyalkylene polyol
It is preferable to introduce a COOX group into the polyoxyalkylene polyol by introducing an OX group and esterifying or urethanizing the resulting polyoxyalkylene polyol containing a carboxylic acid (salt) group. Esterification is performed by reacting a polycarboxylic acid anhydride or a reactive polycarboxylic acid derivative having a reactive carboxylic acid group and a -COOX group.Urethanization is performed by reacting an isocyanate-reactive group (hydroxyl group, primary amino group,
A compound having a secondary amino group, etc.) and a -COOX group is reacted with a polyisocyanate (at least one of the isocyanate groups of the polyisocyanate is a hydroxyl group of the polyoxyalkylene polyol, and at least one of the other
One method is to react the above-mentioned -coax group-containing compound with an isocyanate group), or by reacting a -COOX group with a compound having an isocyanate group.

Examples of these carboxylic acids include maleic acid, fumaric acid, phthalic acid, malonic acid, adipic acid, trimellitic acid, butanetetracarboxylic acid, and reactive derivatives of these polycarboxylic acids such as anhydrides and acid chlorides. .

Examples of the isocyanate-reactive carboxylic acids include dimethylolpropionic acid and amino acid.

X in the -COOX group is a hydrogen atom or a cation, and the cations include ammonium, NR, (R:
At least one is a monovalent organic group such as an alkyl group and the others are hydrogen atoms), phosphonium, alkali metal ions, etc.
Particularly preferred are alkali metal ions. Further, the X of the -coax group of the blocked polyurethane is ultimately a cation, and the -C00M group can be converted into a salt form at any stage.

-CO introduced into the polyoxyalkylene polyol
It is preferable that the number of OX groups introduced is an average of o, oos to 0.8 per molecule of polyoxyalkylene polyol. More preferably 0. The number is 1 to 0.6, particularly 0.04 to 0.4. Moreover, the per hydroxyl group of the polyoxyalkylene polyol is 0.002 to 0.
4, particularly preferably 0.005 to 0.3. This amount is related to the water stability and curing properties of the blocked polyurethane; if it is too small, both the stability and curing properties will be insufficient, and if it is too large, the curing properties will be too high, causing trouble in handling. Therefore, in an introduction method that produces one -COOX group, such as dicarboxylic anhydride, 0.0
05-0.8 MoJL, a compound for introducing the (7)-COOX group is used.

In the carboxylic acid (salt) group-containing polyoxyalkylene polyol into which a -COOX group has been introduced, the average number of hydroxyl groups is preferably more than 2, more preferably 2.
．． 1 or more, especially 2.3 or more. The upper limit is 6, preferably 3.5. In addition, on average less than 1 -C per molecule
By having an OOX group, -CO
A polyoxyalkylene polyol with a large number of OX groups is produced and mixed with a polyoxyalkylene polyol without -COOX groups to produce the desired carboxylic acid (salt).
It is also possible to produce group-containing polyoxyalkylene polyols.

(3) Blocked polyurethane The blocked polyurethane in the present invention is obtained by reacting the carboxylic acid (salt) group-containing polyoxyalkylene polyol, polyisocyanate, and blocking agent. The blocked polyurethane contains about two or more blocked isocyanate groups and is substantially free of free isocyanate groups. This polyurethane can be manufactured by conventional methods. That is, it is obtained by reacting an isocyanate-terminated prepolymer obtained by reacting a polyol and a polyisocyanate with a blocking agent, or by reacting a partially blocked polyisocyanate and a polyol. In the former case, the blocking agent may be used in excess, and unreacted blocking agent may remain in the composition. Usually 1.2
In the present invention, the ratio of hydroxyl groups to polyisocyanate groups (NGOloH) of the carboxylic acid (salt) group-containing polyoxyalkylene polyol is suitably 1.2 to 2.5, preferably 1. .5 to 2.0. Therefore, the blocking agent reacts in excess, ie, equivalents of (NGOloH)-1.

This equivalent ratio is preferably applied to either of the two methods of producing the blocked polyurethane (an excess may be used in one method as described above).
In addition, one COO in block polyurethane
The amount of X group is 0.02 to 3% in terms of −〇〇〇 group,
In particular, it is preferably 0.05 to 1.5%.

The reaction is usually carried out without a solvent or in the presence of a non-reactive solvent. This temperature is usually room temperature to 160℃, especially 60 to 120℃.
It is carried out at ℃. Although a catalyst can be used in this reaction, it is preferred that the catalyst is not an organometallic compound. This is because organometallic compounds reduce the stability of the blocked polyurethane in the final aqueous composition and are prone to the water dispersion problems discussed below. Tertiary amine catalysts are preferred.

When the blocked polyurethane is finally dispersed or dissolved in water, its -000X group is a carboxylic acid group (
That is, it is necessary that X is a cation). -COOX group of polyoxyalkylene polyol is -COOH
In the case of a group, it is necessary to change the hydrogen atom of X to a cation midway through. This conversion can be carried out while the blocked polyurethane is dispersed or dissolved in water, or it can be carried out at any previous stage.

Blocked polyurethane can be dispersed or dissolved in water at any ratio. Preferably, the amount of blocked polyurethane is 5 to 70% by weight, especially 10 to 50% by weight, based on the total of both. The composition may contain other ingredients such as various resins and coloring agents.

(4) As the raw material polyisocyanate and the blocking agent polyisocyanate, polyisocyanates having an average number of functional groups per molecule of 1.8 or more, particularly 2 to 4 are preferred. The incyanate group content is 10% or more, especially 2
0% or more is preferable. As the polyisocyanate, both so-called yellowing polyisocyanates and non-yellowing polyisocyanates can be used, and they can also be used in combination. Preferably, a highly reactive yellowing polyisocyanate is used. Specific polyisocyanates include, for example, tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), naphthalene diisocyanate (NDI), xylylene diisocyanate (XDI), methylene bis(cyclohexyl isocyanate) (H1□MDI), and hexamethylene. Diisocyanate (HDI) There are inphorone diisocyanate (IPDI) and modified products thereof (nurate modified products, prepolymer modified products, carbodiimide modified products, etc.).

As the blocking agent, various kinds of agents used as blocking agents for isocyanate groups can be used. Examples include phenols, mercaptans, oximes, malonic acid diesters, acetylacetone, acetoacetic esters, lactams, and the like.

(5) Polyfunctional compounds Polyfunctional compounds are compounds that have two or more functional groups (hydroxyl groups, amine groups, etc.) that react with isocyanate groups, such as trimethylolpropane, pentaerythritol, sorbitol, sucrose, triethanolamine, etc. In addition to so-called polyfunctional alcohols and saccharides, so-called polyfunctional amines such as ethylenediamine and diethylenetriamine are included.

From the viewpoint of cured product properties, the average number of functional groups is preferably 3 or more, and polyfunctional alcohols and saccharides are particularly preferred.

As for the addition method, when the compound is water-soluble, it may be added to the blocked urethane aqueous solution as it is, or it may be added in the form of an aqueous solution. If the polyurethane is poorly water-soluble, it may be added, mixed and stirred before dispersing the blocked polyurethane in water, or if it is liquid, it may be added to the aqueous blocked polyurethane solution with strong stirring.

The amount added is 0.01 to 1 equivalent to the incyanate group regenerated by heating, and 0.2 to 1.0.
Double equivalents are preferred.

If it is less than this, it is unfavorable in terms of toughness and heat resistance of the cured product that is produced, and if it is added in excess of an equivalent amount, it will remain in the cured product as unreacted substances, resulting in a decrease in performance. Become.

The partially carboxylated polyol used in the present invention has a catalyst in the form of a carboxylate in its molecule, which is necessary to improve the dissociation of the blocking agent and the subsequent curing properties. Since cyanate residues can interact efficiently on a molecular order, curing can be performed using the minimum necessary amount of catalyst and mild curing conditions. In contrast, conventional catalysts are present in the aqueous phase if they are water-soluble.

In the case of an oil-soluble catalyst, the catalyst is liquefied into an aqueous liquid by means such as emulsification and added, but the catalyst is present as particles separate from the blocked product. Another method is to forcibly stir and disperse the oil-soluble catalyst in the aqueous liquid of the blocked product, but the compatibility with the hydrophilic blocked product of the present invention is poor. From the above, the catalytic efficiency is low in the method of adding a normal catalyst,
An excessive amount of catalyst is required, and this excessive amount significantly reduces the thermal stability and long-term stability of the urethane resin after curing. Therefore, in the present invention, it is preferable that substantially no organometallic catalyst is blended into the aqueous composition.

In the present invention, the polyfunctional compound does not react with the blocked polyurethane at room temperature and maintains the form of a stable aqueous dispersion, but upon heating, the polyfunctional compound is present in the molecules of the blocked polyurethane. Because the blocking agent dissociates under relatively mild conditions due to the internal autocatalytic action of the carboxylate salt, it efficiently reacts with the recycled isocyanate to form a highly cross-linked polymer, which improves the toughness of the cured product. , heat resistance etc. are significantly improved.

The composition of the present invention is used as an adhesive or a binder, for example, for fibers, paper, wood, plastics, and other substrates.

Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited to these Examples, and "parts" hereinafter represent parts by weight.

[Example] Example 1 ■Synthesis average molecule of partially carboxylated polyol 125
00 polyoxyalkylene polyol (trifunctional, oxyethylene group 80% by weight) 2500 parts, 17.7 parts of phthalic anhydride, and 3 parts of N,N-dimethylbenzylamine
．． 0 part was added and reacted for 6 hours at 120° C. under a nitrogen stream to obtain a partially carboxylated polyol.

■Synthesis of aqueous blocked polyurethane resin 438.5 parts of tolylene diisocyanate was added to 7 parts of 2,520 parts of the partially carboxylated polyol obtained in (2), and the reaction was carried out at 80"C for 3 hours under a nitrogen stream to form free isocyanate. A urethane prepolymer having 3.07% of groups was obtained.Then, after cooling the prepolymer to 60°C, 187.9 parts of methyl ethyl ketoxime was added dropwise over 30 minutes with stirring.
The reaction was further carried out at 60°C for 60 minutes. After confirming that the free isocyanate groups in the urethane polymer were 0%, an aqueous solution of 4.8 parts of sodium hydroxide dissolved in 6420 parts of water was added and stirred at 30°C for 30 minutes.

(2) Production of composition An aqueous solution prepared by dissolving 46.2 parts of shakerose in 92.4 parts of water was added to the aqueous solution obtained in (2). As a result, an aqueous composition containing a slightly cloudy, low-viscosity blocked polyurethane with a solid content of 31% was obtained.

Example 2 187.9 parts of methyl ethyl ketoxime was added to 438.5 parts of tolylene diisocyanate in 3 hours under a nitrogen stream while taking care not to exceed the internal temperature of 80°C, resulting in a completely transparent product containing 19.3% of free isocyanate groups. A viscous partially blocked isocyanate was obtained. Next, 2520.7 parts of the partially carboxylated polyol obtained in Example 1 (2) was added, and the reaction was carried out at 80°C for 6 hours under a nitrogen stream to remove the free isocyanate in the urethane polymer. After confirming that the base concentration was 0%, an aqueous solution of 4.8 parts of sodium hydroxide dissolved in 6420 parts of water was added, and the mixture was stirred at 30"C for 30 minutes.
Next, an aqueous solution of 92.4 parts of sucrose dissolved in 184.8 parts of water was added to prepare a slightly milky white, low-viscosity blocked polyurethane resin aqueous composition with a solid content of 31%.

Comparative Example 1 The blocked polyurethane aqueous solution in Example 1 before adding the sucrose aqueous solution is used.

Comparative Example 2 The blocked polyurethane aqueous solution in Example 2 before adding the shakerose aqueous solution is used.

Reference Example 1 The blocked urethane resin aqueous composition prepared in Example 1 was applied to a 4,587 m inch piece of polyester Toskin cloth, and then two pieces of this cloth were laminated together at a pressure of 0.3 kg.
/c+a2 lower 120"Cx 5 minutes heat treatment. The peel strength of this treated cloth was measured according to JIS K6301 and the results are shown in Table 1. In addition, the above treated cloth was further heated at 140"C x 6
Table 1 also shows the peel strength results after 0 minute treatment.

Reference Examples 2 to 4 The same procedure as Reference Example 1 was conducted except that the aqueous compositions of Examples 1 and 2 were used and the treatment temperature and time were changed, and the results are shown in Table 1.
It was shown to.

Comparative Examples 3 to 6 Using the blocked urethane resin aqueous liquid of Comparative Example 2,
Table 1 shows the results of a test similar to that of the reference example.

[Effects of the Invention] Although the reactive aqueous composition of the present invention has a long and stable pot life, the blocking agent is significantly effectively dissociated by heating. The reaction progresses well and produces a highly cross-linked polymer, providing a resin that is tough and heat resistant. Furthermore, the highly efficient reaction described above significantly increases the adhesive force to the substrate, forming a strong adhesive layer.

Claims (1)

[Claims] 1. A carboxylic acid (salt) group-containing polyoxyalkylene polyol containing 50% by weight or more of oxyethylene groups and having a -COOX group (X: hydrogen atom or cation) at the end of the main chain; A reaction product of a polyisocyanate having isocyanate groups in an excess equivalent amount to the hydroxyl groups of the polyisocyanate, and a blocking agent in an amount corresponding to the excess equivalent of the polyisocyanate, and when X is a hydrogen atom, A carboxylic acid group-containing blocked polyurethane obtained by converting X into a cation at any stage, a polyfunctional compound in an amount of 0.01 to 1 times the equivalent of the recycled isocyanate group of the blocked polyurethane, and water as essential components. an aqueous composition. 2. Carboxylic acid (salt) group-containing polyoxyalkylene polyol has an average of more than 2 hydroxyl groups per molecule and 0
．． Carboxylic acids containing 005 to 0.8 -COOX groups (
The composition according to claim 1, which is a polyoxyalkylene polyol containing a salt) group. 3. The polyoxyalkylene polyol has an oxyethylene group content of 70 to 90% by weight and a molecular weight per hydroxyl group of 30.
0 to 3000, with an average number of hydroxyl groups of 2.3 to 3.5, and a carboxylic acid (salt) group-containing polyoxyalkylene polyol derived from the polyoxyalkylene polyol has an average number of hydroxyl groups of 2.3. ~3.5, average -COOX base 0.04~0.4
The composition according to claim 1, which is