JPH0365372B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a rubber chip binder that binds crushed rubber or polyurethane elastomer to form an elastic body. The effective use of waste rubber such as tire scraps is an important issue, and various countermeasures have been attempted, including pulverizing waste rubber and binding it with a binder to create an elastic body, which can be used as flooring and paving materials. A method of using it as an example is being implemented. In addition to rubber latex, there are various binders for binding crushed products such as waste rubber and recycled rubber, and one of them is a prepolymer having an isocyanate group at the end of the molecule. The urethane prepolymer is cured by moisture, becoming an elastic body and at the same time forming an adhesive layer that binds the crushed rubber material. There are two methods of bonding rubber and polyurethane elastomer chips to form an elastic body: the prefabricated method, in which plates, blocks, etc. are made using formwork in a factory, and then laid at the construction site; There is an on-site construction method that combines this. The problem with the on-site construction method is that it takes a long time to harden in the winter when both the temperature and humidity are low, while it hardens quickly in the hot and humid summer, making work difficult. Methods of curing prepolymers with isocyanate groups at the molecular ends using moisture include moisture-curing one-component urethane paints and moisture-curing one-component urethane sealants.To shorten the curing time, known urethanization catalysts are used. Certain tertiary amines or organometallic compounds such as dibutyltin dilaurate have been used. These urethanization catalysts are also effective in shortening the curing time of rubber chip binders. However, regarding how to extend the curing time,
In the case of the above-mentioned paints, sealants, etc., there is no need to extend the curing time, so such a method has not been known. As a result of various studies on extending the curing time so that sufficient working time can be obtained even under high temperature and high humidity conditions, the present invention was arrived at. That is, the present invention is as follows. 1. A rubber chip binder that binds crushed rubber or polyurethane elastomer to form an elastic body contains 0.1 to 10% by weight of an organic acid halide,
A rubber chip binder comprising a urethane prepolymer having an isocyanate group at the molecular end. The organic polyisocyanate used in the production of the urethane prepolymer having an isocyanate group at the molecular end of the present invention is 2.4-tolylene diisocyanate, 2,6-tolylene diisocyanate, or a 80/20 or 65/35 weight ratio of both isocyanates. Mixtures, diphenylmethane diisocyanate, crude products of so-called liquid diphenylmethane diisocyanate and tolylene diisocyanate liquefied by various conventionally known methods described in Japanese Patent Publication No. 38-4576, etc.
Polymethylene polyphenyl polyisocyanate (crude product of diphenylmethane diisocyanate)
It is one kind or a mixture of two or more kinds of conventionally known aliphatic isocyanates such as conventionally known aromatic polyisocyanates such as dicyclohexylmethane diisocyanate and isophorone diisocyanate. Polyols used to produce urethane prepolymers by reacting with these organic polyisocyanates include polyhydric alcohols such as glycerin, trimethylolpropane, and pentaerythritol, water, ethylene glycol, propylene glycol, glycerin, pentaerythritol, and sorbitol. , polyether polyols obtained by addition polymerizing propylene oxide or propylene oxide and ethylene oxide to polyhydric alcohols such as sucrose or similar substances, polytetramethylene ether glycols, polycaprolactone polyols, polyethylene adipate, etc. polyester polyols, polybutadiene polyols, esters of higher fatty acids containing hydroxyl groups such as castor oil, and polymer polyols obtained by grafting vinyl monomers onto polyether polyols or polyester polyols. When producing a urethane prepolymer having an isocyanate group at the end of the molecule by reacting a polyisocyanate with a polyol, the polyisocyanate is used in excess of the equivalent amount, and the isocyanate content of the obtained urethane prepolymer is adjusted to 2 to 20% by weight. (The following percentages indicate weight percentages, except in specific cases.)
It is preferably 5% to 15%. If the isocyanate group content is lower than this range, the bonding strength of the rubber chips will be weak, and if it is higher than this range, the binder layer will be prone to foaming.
Also, problems such as hardness and brittleness occur. Among organic acid halogenides, organic acid chloride and organic acid bromide are used in the present invention. Specific examples include caproic acid chloride,
Lauric acid bromide, palmitylic acid chloride, stearic acid chloride, malonic acid chloride, tartaric acid bromide, adipic acid chloride,
Aliphatic mono- or polyhydric organic acid halogenides such as sepacic acid chloride, beyzoyl chloride,
Aromatic carboxylic acid halogenides such as n-, i- and tere-phthalic acid chloride, naphthalenecarboxylic acid bromide, naphthalenedicarboxylic acid chloride, biphenylcarboxylic acid chloride, biphenyldicarboxylic acid bromide, trimellitic acid trichloride, trimethylbenzenecarboxylic acid chloride, alkylallylcarboxylic acid halogenides such as tert-butylbenzenecarboxylic acid bromide, allylalkylcarboxylic acid halogenides such as phenyl acetate chloride, naphthalene acetate bromide, biphenyl acetate chloride, tolylpropionic acid chloride, and fats such as cyclopentanecarboxylic acid chloride. These include cyclic carboxylic acid halogenides. When adding and mixing these organic acid halogenides to the urethane prepolymer, the appropriate amount to use is 0.1 to 10% based on the prepolymer, and the amount added can be adjusted depending on the temperature and humidity at the time of construction, the content of organic acid halide groups, etc. do. Generally, if it is less than 0.1%, there is no effect, and if it is more than 10%, the curing speed of the rubber chip binder becomes too slow and is not suitable for practical use. If the viscosity of the rubber chip binder is too high, a solvent such as acetone, methyl ethyl ketone, ethyl acetate, toluene, etc. can be added, and if necessary, fillers, colorants, etc. can also be added. The method of applying the rubber chip binder of the present invention is to uniformly apply the required amount of rubber chip binder to the surface of the rubber chips while stirring the rubber chips such as waste rubber, recycled rubber, polyurethane elastomer, etc. in a mixer, and then apply the required amount of rubber chip binder to the surface of the rubber chips. An elastic body is obtained by spreading the rubber chip binder to a thickness of 100 mL and leaving it overnight to harden the rubber chip binder due to the moisture in the air. The weight ratio of rubber chips and rubber chip binder is preferably 95/5 to 60/40, especially 85/5.
A weight ratio of 15-75/25 is recommended. Examples will be described below. Example 1 660 g of polyoxypropylene glycol with an average molecular weight of 3000 and diphenylmethane diisocyanate
340 g was reacted in a nitrogen stream at 80°C for 2 hours to produce a prepolymer. This prepolymer has a first
Add and dissolve 50g of the organic acid halide listed in the table, and the isocyanate group content is 8.0% and the viscosity is 8.0%.
A rubber chip binder of 3200 cps/25°C was obtained. Example 2 The rubber chip binder obtained in Example 1 and waste rubber chips (size 1 to 3 mm) were mixed at a weight ratio of 1:4 using a stirrer to uniformly adhere the rubber chip binder to the surface of the rubber chips. . Table 1 shows the results of spraying this mixture on a flat plate in a room at 35±1°C and relative humidity of 70±10% and measuring the time until compaction became impossible (pot life). . In addition, these mixtures were spread on the formwork and rolled using a trowel to create a sheet with a thickness of 7 to 8 mm.
After curing for 48 hours at 23±1℃ and relative humidity of 50±5%, and further curing for 24 hours at 50±1℃ and relative humidity of 70±±5%, the physical properties were measured and the results are shown in Table 1. . As is clear from Table 1, by adding an organic acid halide to the prepolymer, the pot life of the rubber chip binder is extended, and
The physical properties of the elastic body using this rubber chip binder were improved.

[Table] Example 3 257.3 g of diphenylmethane diisocyanate and 742.6 g of polyoxypropylene glycol having an average molecular weight of 3000 were reacted at 80° C. for 3 hours in a nitrogen stream to obtain a prepolymer. A rubber chip binder was produced by adding isophthalic acid chloride in the amount shown in Table 2 to this prepolymer. Example 4 The rubber chip binder obtained in Example 3 and waste rubber chips (size 1 to 3 mm) were mixed at a weight ratio of 1:3 using a stirrer, and the rubber chip binder was uniformly adhered to the surface of the waste rubber chips. Ta. The above mixture was treated in the same manner as in Example 1, and the pot life and sheet properties were measured, and the results shown in Table 2 were obtained. Isophthalic acid chloride in the prepolymer is approx.
Addition of 0.1 to 9% has almost no effect on the viscosity of the rubber chip binder, and the pot life becomes longer.
It is clear from Table 2 that the physical properties of the elastic body are improved.

【table】

Claims (1)

[Claims] 1. A rubber chip binder that binds crushed rubber or polyurethane elastomer to form an elastic body contains 0.1 to 10% by weight of an organic acid halide,
A rubber chip binder for elastic bodies, characterized in that it is made of a urethane prepolymer having isocyanate groups at the molecular ends.