JPH0223586B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a pot life extender for solvent-type polyvinyl acetate adhesives. More specifically, we extend the pot life of synthetic resins, especially solvent-based polyvinyl acetate adhesives used when bonding polyvinyl chloride flooring materials to the base, and provide good workability. This is related to drugs. Note that the pot life as referred to in the present invention is as follows.
i.e. adhesive on waterproof veneer or asbestos board.
300g/ with a comb trowel specified in JIS A-5536
JIS A- coated with ^m2 and cut into 10 x 10 cm pieces on top.
Place a tile specified in 5705 and place 200 on top of the tile.
After placing a weight of g for 10 seconds, immediately remove the tile.
The time it takes for the adhesive to adhere to 50% or more of the area of the glue line on the back of the tile (the linear part where the comb of the adhesive contacts the back of the tile) as determined by visual inspection. Polyvinyl acetate-based adhesives are used to adhere flooring materials made of synthetic resin, particularly polyvinyl chloride, to a base such as mortar. This type of adhesive has various advantages such as being relatively inexpensive compared to other adhesives, having good affinity for flooring materials such as polyvinyl chloride, and being easy to handle. It is something that you have.
This type of adhesive can be roughly divided into two types: an aqueous type called an emulsion and a solvent type using an organic solvent as a medium. While the former is environmentally preferable, it has relatively weak adhesive strength and poor water resistance. Therefore, solvent-based adhesives have become indispensable in areas where adhesive strength and water resistance are required. The above-mentioned solvent-based adhesive is different from an emulsion-based adhesive in that when it is applied to a base, the solvent evaporates and the adhesive itself solidifies. Since this solvent volatilizes at a fairly fast rate, there is only a short amount of time (pot life) between applying the adhesive to the base and pasting the flooring on top, and if the timing of adhesion is delayed, the flooring Problems such as peeling, warping, and blistering were caused, and various restrictions were attached to adhesion work, which was undesirable. It is known that this pot life is shortened at high temperatures in the summer, but also shortened at low temperatures in the winter when the temperature is below 0°C. The reason for this winter phenomenon has not been determined, but it is thought to be as follows. In other words, it is assumed that this is because when the temperature becomes low, the compatibility of various additives mixed in the composition decreases, the balance of the system is lost, and the solvent becomes more likely to volatilize directly. As an attempt to solve this problem, adding a pot life extender has conventionally been carried out. Although the following pot life extenders have been proposed in the past, no one has yet been found that provides the required pot life over a wide temperature range. (i) Amines: stearylamine, laurylamine, etc. (ii) Glycerin esters: glycerin monostearate, glycerin monobehenate, diglycerin mono(di)stearate, polyoxyethylene diglycerin monostearate, etc. (iii) Propylene glycol esters: propylene glycol monostearate, etc. (iv) General surfactants: polyoxyalkylene alkyl ether, sorbitan ester, alkyl sulfate, alkyl phosphate, etc. Among the above, amines and glycerin esters are used at room temperature. It is effective in high temperature areas in summer. However, in the low temperature range below 0°C, it is not effective and the pot life is shortened. Therefore, it is not suitable for cold regions. Propylene glycol esters do not show very significant effects even at high temperatures. Surfactants have no effect in the room temperature to high temperature range.
Furthermore, these compounds reduce the viscosity of the adhesive,
Reduces tack (tackiness). Generally speaking, those that dissolve transparently in the adhesive solution are ineffective. Furthermore, those with a high molar addition of alkylene oxide and those containing unsaturated groups also have high solubility and are less effective. The present invention solves the above conventional problems and provides a pot life extender for solvent-based polyvinyl acetate adhesives that exhibits a good pot life extension effect over a wide temperature range from summer to winter, especially at low temperatures. This is what we provide. The usable life extender of the present invention is used when a solvent-based polyvinyl acetate adhesive is applied especially at high temperatures in the summer or at low temperatures in the winter. Furthermore, the solvent in the adhesive tends to volatilize and the adhesive itself tends to solidify, and the time the adhesive can be used in a good bonding state is extremely short, which hinders the bonding operation. By adding this agent to a solvent-based polyvinyl acetate adhesive, it is an adhesive additive that maintains the adhesive in a good adhesive state for a long time over a wide temperature range from summer to winter. That is, the present invention provides: 1. A pot life extender for a solvent-type polyvinyl acetate adhesive composition represented by the following general formula (). [However, in the formula, Y ₁ and Y ₂ represent H or COR, and R represents an alkyl group or hydroxyalkyl group having 11 to 21 carbon atoms. ] and 2 consisting of a compound represented by the following general formula () and a stearyl alcohol ethylene oxide adduct (abbreviated as compound ()) with an average number of added moles of 0.5 to 1.5 moles, and the content of the former is
A pot life extender for solvent-based polyvinyl acetate adhesive compositions containing 50% by weight or more. [However, in the formula, Y ₁ and Y ₂ represent H or COR, and R represents an alkyl group or hydroxyalkyl group having 11 to 21 carbon atoms. ] Its gist is as follows. The compound represented by the general formula () is an organic boric acid ester obtained by esterifying boric acid, glycerin, and fatty acid (or fatty acid halide) by a conventional method. Preferred specific examples include:
In COR, R is _C11 lauric acid residue, _C13 myristic acid residue, _C15 palmitic acid residue, _C17
Examples include compounds having a stearic acid residue at _C17 , a hydroxystearic acid residue at C17, and a behenic acid residue at _C21 . Furthermore, the average number of added moles that can be used in the present invention is 0.5
Stearyl alcohol ethylene oxide adduct (compound) is ~1.5 moles, which means that 1 mole of stearyl alcohol contains ethylene oxide on average.
It means a compound added with 0.5 to 1.5 moles, and may substantially contain unreacted stearyl alcohol, an adduct of 2 moles or more of ethylene oxide, etc. Stearyl alcohol here is a mixture of solid alcohols whose main component is stearyl alcohol with 18 carbon atoms, and is catalytically reduced using natural fats and oils such as animal oils such as pine whale oil and beef tallow, and vegetable oils such as soybean oil. Alternatively, it refers to stearyl alcohol of various purity obtained by hydrogenation of unsaturated alcohol containing a large amount of alkyl groups having 18 carbon atoms, and any solid alcohol containing 50% by weight or more of stearyl alcohol can be used in the present invention. I can do it. When the average number of moles of ethylene oxide added is 2 moles or more, the compound () becomes more compatible with the adhesive and no longer exhibits any significant effect. Furthermore, if the average number of moles added is less than 0.4 moles, the unreacted raw material stearyl alcohol content will increase, and the pot life extension effect will be small. If the number of carbon atoms in the alkyl group of the compound () is less than 16, it will increase the compatibility with the adhesive, which is undesirable. If the number of carbon atoms is more than 20, the compatibility with the adhesive will deteriorate, or large crystals will precipitate, making it ineffective. . The compound of general formula () can extend pot life over a wide temperature range. By using the compound of the general formula () and the compound () together, the pot life can be further extended, and good tackiness can also be maintained. Also general formula ()
When using a mixture of the compound (2) and the compound (2), by containing the former in an amount of 50% by weight or more, it is possible to obtain an adhesive composition that not only has an excellent pot life extension effect but also has good tackiness. When the compound of general formula () is 50% by weight or less,
Although it has the effect of extending pot life, it lacks tact, which hinders workability. Such a compound is added to and mixed with a solvent-type polyvinyl acetate adhesive. The polyvinyl acetate resin used in this type of adhesive is a homopolymer of vinyl acetate, vinyl acetate and olefins such as ethylene or propylene, or unsaturated acids such as acrylic acid, methacrylic acid, maleic acid, or their like. Copolymer with alkyl ester vinyl chloride etc.
This copolymer contains 50% by weight or more of vinyl acetate. The organic solvent is not particularly limited as long as it can dissolve the above-mentioned resin. Alcohols, especially methanol and ethanol, which are industrially available at low cost and relatively safe, are often used. Other examples include ethyl acetate, toluene, and acetone. This type of adhesive also usually contains calcium carbonate,
In addition to fillers such as talc, clay, and asbestos, and tackifiers such as rosin, modified rosin, and petroleum resin, there is nothing wrong with using commonly used additives. The pot life extender of the present invention is usually added in an amount of 0.05 to 5% by weight to the polyvinyl acetate resin of the adhesive as described above during the production of the adhesive. Of course, in this case, it is also possible to use a conventionally known pot life extender in combination. As mentioned above, the pot life extender of the present invention has the following properties: (1) the pot life is extended at high temperatures in summer and provides good workability;
It has excellent effects such as extending pot life and providing good workability even at low temperatures below .degree. C., and (3) providing an adhesive composition with good tack. Next, the present invention will be described in more detail with reference to Examples. Examples 1 to 9 and Comparative Examples 1 to 10 First, a methanol solution of polyvinyl acetate (solid content
50%) 100g of 5 compounds of formula () with different substituents shown in Table 1, and formula () and compound ()
2g of each of the four types of pot life extenders with different mixing ratios and 20g of methanol were added and mixed. Further, 50 g of calcium carbonate and 50 g of asbestos were added and mixed with stirring to obtain an adhesive. On the other hand, for comparison, 10 types of adhesives were similarly obtained using conventional pot life extenders shown in Tables 2 and 3, and these were used as comparative examples. The pot life of these adhesives at 25°C, 0°C, and -5°C was measured as originally defined. The results are also listed in each table. From these tables, it can be seen that products using the pot life extender of the present invention have a good pot life extension effect in a wide temperature range from high to low temperatures, and in particular, when used in combination with the compound of formula () and compound () It can be seen that the effect is remarkable. This material also had good tackiness. Tackiness: When measuring the pot life at 0°C, the strength of adhesion is determined by sensory evaluation, and the best value is used to compare each sample. The results were evaluated as △, and those that were inferior were evaluated as ×.

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Claims (1)

[Claims] 1. A pot life extender for a solvent-type polyvinyl acetate adhesive composition represented by the following general formula (). [However, in the formula, Y ₁ and Y ₂ represent H or COR, and R represents an alkyl group or hydroxyalkyl group having 11 to 21 carbon atoms. ] 2 A solvent-type polyvinyl acetate consisting of a compound represented by the following general formula () and a stearyl alcohol ethylene oxide adduct with an average number of added moles of 0.5 to 1.5 moles, and in which the content of the former is 50% by weight or more. A pot life extender for adhesive compositions. [However, in the formula, Y ₁ and Y ₂ represent H or COR, and R represents an alkyl group or hydroxyalkyl group having 11 to 21 carbon atoms. ]