JPS5840972B2 - Curing agent for water-wet substances made of urethane prepolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a curing agent for water-wet materials consisting of a urethane prepolymer.

Unless a special polyol is used, the urethane prepolymer obtained by reacting a polyol with an excess of an organic isocyanate compound has poor hydrophilicity, so it easily reacts with the water contained in the wetted material. Therefore, ordinary urethane prepolymers cannot be used as curing agents for wetted materials, and because they are liquid, they are difficult to mix uniformly with wet powders and their transportation is difficult. , handling, etc. was troublesome.

As a result of extensive research into curing agents for wet substances containing a large amount of water, the present inventors found that urethane prepolymers containing quaternary ammonium salts in their molecular chains have hydrophilic properties and can be used to cure wet substances. It was discovered that the reaction with the water in the material becomes easy, the wet material is cured, and the resulting cured product has excellent properties such as mechanical strength.

In addition, the urethane prepolymer is solidified by the ionic action of the quaternary ammonium salt in the molecular chain, which causes ionic crosslinking between molecules and increases the viscosity of the prepolymer. I found that it becomes.

This invention has been achieved based on the above findings, and is made into a urethane prepolymer having at least two NCO groups at the end and a quaternary ammonium salt in the molecular chain, and which is made into powder. This is a curing agent made of a urethane prepolymer, which is characterized by the fact that it has the following properties:

The urethane prepolymer of the present invention comprises an organic isocyanate compound, a tertiary amine compound having at least one hydroxyl group, and a quaternary amine compound for quaternizing the tertiary amine group of the tertiary amine compound. It is obtained by reacting with a curing agent.

The organic isocyanate compound mentioned above is a polyisocyanate compound such as aliphatic, aromatic, alicyclic diisocyanate button and triisocyanate which are used in the production of ordinary urethane prepolymers, and tolylene diisocyanate is preferred. (TDI), phenylene diisocyanate 4, 4'-diphenylmethane diisocyanate (MDI), 1,6-hexamethylene diisocyanate, isophorodiisocyanate (IPDI) 4,
Examples include 4'-dicyclohexylmethane diisocyanate.

The tertiary amine compound has at least one OH group at its end that reacts with the NCO group of the organic isocyanate compound, and is represented by the following chemical formula.

In the above formula, R1, R2z R3 are an alkylene group or an oxyalkylene group, and R, JR5 are an alkyl group or an oxyalkyl group.

Among the above formulas, diol type formula (2) is particularly preferred, and the above formula is used alone or in combination with the above formula (2) as a reaction terminator for the urethane prepolymer, and triol type (2) is Because it reacts three-dimensionally, it is suitable for imparting heat resistance to cured products.

Specific examples of the above tertiary amine compounds are dimethylethanolamine, diethylethanolamine, di-n
-Butyl ethanolamine I is a low molecular compound such as a hexagram, and an alkylene oxide adduct of a dialkylamine with an average molecular weight of about 2000. It is an alkylene oxide adduct of monoalkylene amine with an average molecular weight of about 3,000, and in formula (2), it is an alkylene oxide adduct of triethanolamine, triisopropanolamine, and these amines as starting materials and has an average molecular weight of about 2,000. It is something.

(c) A quaternizing agent for converting the tertiary amine group of the tertiary amine compound into a quaternary ammonium salt, a halogenated alkyl, a halogenated organic acid-A-, a sulfuric ester, etc. Compounds include propyl chloride,
Examples include benzyl chloride, monochloroacetic acid, butyl bromide, dimethyl sulfate, and diethyl sulfate.

The above-mentioned quaternizing agent generates a quaternary ammonium salt in the molecular chain and imparts hydrophilicity to the urethane prepolymer.

The degree of hydrophilicity depends on the concentration of the quaternary ammonium salt, and the concentration of quaternary nitrogen contained in the quaternary ammonium salt is calculated by the following formula.

However, in the above formula, M is the number of moles of the tertiary amine compound in the formulation, and A is the molar ratio of the quaternizing agent to the tertiary amine compound (however, if A is larger than 1.0, it is 1.0 ), W is the total weight (g) of the isocyanate compound, tertiary amine compound button, and polyol in the formulation.

1. -, the amount of polyol is when used in combination with a tertiary amine compound, and the combination of polyol will be described later.

The quaternary nitrogen concentration calculated using the above formula (■) is 0.2 to 5.0
It is preferable that the weight φ is less than 0.2 weight φ, the hydrophilicity of the urethane prepolymer will be poor, and if it exceeds 5.0 weight φ, the water resistance of the cured product will decrease and it will be inferior in practicality.

The amount of the quaternizing agent added to the tertiary amine compound is preferably equal to or slightly less than the theoretical value.

Since the quaternizing agent generally has an irritant or peculiar odor, if the amount of the quaternizing agent is too large, the peculiar odor will remain in the obtained urethane prepolymer, which is undesirable.

The above-mentioned quaternizing agent may be added during the prepolymer production reaction, or may be added after the prepolymer production.

Conditions for the quaternization reaction using a quaternizing agent vary depending on the type of quaternizing agent, but can be carried out in a temperature range of room temperature to 130°C.

Among the quaternizing agents, sulfuric acid ester and monochloroacetic acid are used at relatively low temperatures, and benzyl chloride is used at around 100°C.

Preferably, the prepolymer obtained as described above is a solid body, and its free NCO% is 5 to 25% by weight.

In order to use this urethane prepolymer as a curing agent, the obtained solid is ground into powder.

When producing the urethane prepolymer of the present invention, a polyol can be added in addition to the above-mentioned tertiary amine compound and quaternizing agent.

In particular, when using a low molecular weight tertiary amine compound, it is preferable to use a polyol in combination in order to adjust the concentration of ionic groups and widen the distribution of ionic groups.

However, when a tertiary amine compound and a polyol are used together, the tertiary amine compound has greater reactivity with the isocyanate compound, so only the tertiary amine compound reacts with the isocyanate compound, and the resulting urethane prepolymer contains The icane groups of are not uniformly distributed.

A two-step process should be adopted in which the acid polyol is reacted with an isocyanate compound in advance to form a prepolymer, and then a tertiary amine compound is added and reacted.

The above method of using a low molecular weight tertiary amine compound in combination with a polyol is convenient when producing a wide variety of urethane prepolymers in small quantities, while the method of using only a high molecular weight tertiary amine compound is This is advantageous in the case of mass production of various varieties.

The polyols mentioned above are those commonly used in polyurethane production.

As the ether type polyol, propylene glycol type, butylene glycol type, tetramethylene glycol type polyols having an average molecular weight of 2500 or less, other diols, and triols can be used.

Examples of ester polyols include polycondensates of adipic acid and various glycols (e.g., ethylene glycol propylene glycol, diethylene glycol, etc.), polycaprolactone, etc., with an average molecular weight of 2,500 or less, or 1,4-butanediol, ethylene glycol, etc. Chain extenders can be used.

In producing the above-mentioned urethane prepolymer, fillers and solvents can be added as effective agents although they do not directly participate in the reaction of the prepolymer.

The above urethane prepolymer is a material in which water is attached to and contained in organic or inorganic powder, granular, or fibrous materials such as earth and sand, ceracola, wood flour, grass, and glass fibers. It is used as a curing agent alone or in mixtures.

By mixing a filler with the above urethane prepolymer, the prepolymer is coated on the surface of the filler, so it is better to use a prepolymer coated with a filler than to use only prepolymer powder. The amount of prepolymer may be small, and the strength of the cured product may be increased by the filler.

Since the action of the filler is related to the particle size of the wet material to be cured, fillers with a particle size of several mm can be used more widely than ultrafine particles.

The filler material reacts with the raw material components used in prepolymer production.
As long as it is soluble, it may be either inorganic or organic, and specific examples include ultrafine particulate silica, calcium carbonate, aluminum silicate, diatomaceous earth, glass peas, shirasu balloons, and phenolic resin powder.

Since the prepolymer of the present invention tends to solidify due to ionic bonds, the solvent added during prepolymer production is used to prevent solidification during the prepolymer production reaction, or when coating the surface of the filler with the prepolymer. It is used to lower the viscosity of prepolymer liquids.

Useful solvents include those that do not react with the prepolymer, have good solubility in the prepolymer, have a low boiling point, and are easily scattered, such as acetone, methyl ethyl ketone, and the like.

In addition to the above-mentioned fillers and solvents, anti-aging agents, ultraviolet absorbers, reaction accelerators, reaction retardants, pigments, etc. commonly used in polyurethane can be appropriately added during prepolymer production.

The present invention will be specifically explained below using examples.

In the examples, "parts" in the compounding amount are "parts by weight" and "parts" are "parts by weight."

Examples 1 to 3 (1) Production of quaternized ammonium salt In a three-necked flask equipped with a stirrer, a thermometer, and a dropping funnel,
Processed 119 parts of methyl jetanol. The flask was cooled in an ice-water cooling bath, and while stirring the liquid, 126 parts (equivalent molar amount) of dimethyl sulfuric acid was added from the dropping funnel at a rate so as to maintain the liquid temperature at 30 to 35°C. After adjusting the temperature and adding the drops, remove the cooling tank, raise the temperature of the liquid to 70°C, react for 1 hour, cool slowly to room temperature, and obtain a pale yellow transparent viscous liquid. A quaternized ammonium salt is obtained, which is referred to as quaternized compound A.

! . In addition, 149 parts of triethanolamine was used in place of the above-mentioned methyljetanol, and a quaternized ammonium salt was obtained in the same manner as above, and this was designated as quaternized product B.

(2) Production of prepolymer Add the above quaternized ammonium salt, isocyanate compound, and if necessary 1°4-butanediol to a three-neck flask equipped with a stirrer, a thermometer, and a nitrogen gas inlet.
Stir while introducing nitrogen gas, raise the temperature from room temperature to 70'C4, add dibutyltin dilaurate as a catalyst and continue to raise the temperature, it becomes a clear, homogeneous liquid at 120°C, and at 150'C4. When heated, it rapidly became viscous in about 1 minute, and the viscous liquid was immediately transferred to a sealed container and aged at room temperature for 1 day, turning into a pale brown transparent solid.

This solid material was ground in a mortar to obtain a powdery urethane prepolymer containing a quaternary ammonium salt.

The blending amounts of each of the above components and the properties of the prepolymer are shown in the table below.

(3) Curing test (a) Wet wood flour produced in a sawmill (particle size 1 to
Add 100 parts of the prepolymer powder from Example 1 above to 300 parts (water content: 60%), mix uniformly, and press-fill this mixture into a cylindrical mold with an inner diameter of 50 mm and a length of lQQmi. and cured.

The obtained cured product had a specific gravity of 0.6 and a compressive strength of 32.0.
/cIrL2, and has high strength with a compressive strain rate of 13φ.

This cured product is suitable for molded objects such as dolls, building materials, and the like.

(b) Add 10 parts of the prepolymer powder of Example 2 to 120 parts of No. 4 silica sand (moisture content: 20), mix uniformly, and press-fill into the cylindrical mold to form a cured product. Obtained.

This cured product has a compressive strength of 55.6 kg/crA,
With a compressive strain rate of over 1.8, this prepolymer is useful as a hardening agent for wet soil.

(e) Mix 100 parts of calcined gypsum, 60 parts of water, and 0.3 parts of triethylenediamine (trade name: DAPCO), immediately add 10 parts of the prepolymer powder of Example 3, mix uniformly, and mix this mixture. It was filled into a mold of 200 nm square and 8 mm thick, and cured at 80° C. for 7 hours under a pressure of about 5 tons.

After the cured product was left at room temperature for several days, physical properties were tested, and the result was a gypsum board with good flexibility, with a tensile strength of 18 kg/CfIL2 and a bending strain rate of 7%.

Example 4 2000 parts of polypropylene glycol with an average molecular weight of 2000 and 522 parts of TD■-80 were added to a four-eye flask equipped with a stirrer, a thermometer, a dropping funnel, and a nitrogen gas inlet, and the mixture was heated at 90 to 100°C. Heat for 1 hour, then 30
After cooling to ~35°C, 119 parts of methyljetanolamine and 119 parts of methyl ethyl ketone as a solvent were added dropwise from a dropping funnel, and the temperature was raised to 60~70°C and reacted for about 1 hour.Then, the liquid temperature was lowered to 40~50°C. As °C, TD■-
After adding 635 parts of 80 and maintaining the above liquid temperature for about 30 minutes, the liquid temperature was further raised to 50 to 60°C, and 90 parts of monochloroacetic acid and 90 parts of methyl ethyl ketone were gradually added.
Hold for about 1 hour.

The obtained prepolymer was a purple-brown viscous liquid with a quaternary nitrogen concentration of 0.4% and free NC of 9.9%.

When 80 parts of the above prepolymer was gradually added to a Shirasu balloon having a water content of 0.5% with stirring and uniformly dispersed, methyl ethyl ketone was scattered to obtain a prepolymer powder coated with a filler.

Next, the wood flour 300 used in the hardening test a of Example 1
Short glass fiber (length 13wL, Nittobo Co., Ltd. C8-
Add 15 parts of 13E-221) and stir well, add and mix 100 parts of the above prepolymer powder as a curing agent to this mixture, and fill it into the same mold as in curing test a of Example 1. hardened.

This cured product has a specific gravity of 0.45 and a compressive strength of 12 kg/crI.
I2, the compressive strain rate is 25 coefficients or more, and the structure is similar to soft fiberboard, which is a building material.

The shape of this cured product did not change even when immersed in water.

As explained above, since the curing agent of the present invention contains a quaternary ammonium salt in its molecular chain, it has good hydrophilicity and good reactivity with moisture in wet substances. The strength of the obtained cured product is excellent.

Moreover, unlike a liquid urethane prepolymer, this curing agent is in the form of a powder, so that it is uniformly mixed with the wet substance, resulting in a uniform curing action.

Claims (1)

[Scope of Claims] 1. A urethane prepolymer having at least two NCO groups at the ends and containing a quaternary ammonium salt in the molecular chain, and which is in the form of a powder. Curing agent for water-wet materials consisting of polymers. 2 The quaternary nitrogen concentration is 0.2 to 5.0% by weight, and the free isocyanate is 5 to 25% by weight.
A curing agent for water-wetted substances comprising the urethane prepolymer described in 1.