JPS6145672B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a solid filler/primer suitable for α-cyanoacrylate adhesives, which is applied or rubbed onto the surface to be powdered to fill and close small pores on the surface. ,
The aim is to improve porous materials such as wood, paper, and concrete, which were previously considered unsuitable.
- Provides a solid primer that accelerates set time, improves adhesive strength, is easy to handle, and has good stability when bonding with cyanoacrylate adhesives. α-Cyanoacrylate adhesive has an alkyl α-cyanoacrylate monomer as its main component,
It is an adhesive that also contains stabilizers, thickeners, etc.
Due to the unique anionic polymerizability of α-cyanoacrylate monomers, it can firmly bond almost all materials such as metals, rubber, and plastics in a short time, with the exception of some materials such as polyethylene and polypropylene. Widely used as an instant adhesive. However, because this adhesive has extremely good permeability, it is possible to achieve penetrating bonding, which is difficult to do with other adhesives.
When using porous materials such as paper, cloth, concrete, mortar, and foam products as adherends, the adhesive penetrates into the small pores, voids, and grooves of the adherend, resulting in lack of glue in the adhesive layer. Adequate adhesion is often difficult. Conventionally, in such cases, attempts have been made to add and dissolve a high molecular weight polymer as a thickener to the α-cyanoacrylate adhesive to increase the viscosity of the adhesive and prevent penetration, but in this case, α-cyanoacrylate Since polymers, which can be called impurities, are added, the stability of the adhesive tends to decrease and the shelf life tends to be shortened. Furthermore, even if penetration could be prevented by increasing the viscosity of the adhesive, when bonding wood, for example, the wood surface is usually acidic, which delays or prevents the anionic polymerization of the α-cyanoacrylate monomer. In terms of phenomena, there were problems such as a significantly slow set time and insufficient adhesive strength. In this case, substances that promote the anionic polymerization of α-cyanoacrylate, such as inorganic basic substances such as caustic soda, caustic potash, and soda carbonate, organic basic substances such as organic amines and organic imide compounds, quaternary ammonium salts, It has been proposed to use compounds such as phosphonium salts, organometallic compounds such as titanates, metal chelate compounds, etc. as primers. However, since these primers are usually dissolved in a solvent such as water or an organic solvent and used as a solution, it is difficult to store the primer, the process of applying the liquid primer is complicated, and furthermore, after applying the primer, The required adhesive performance cannot be obtained unless the adhesive is used after the solvent has evaporated, so after applying the primer, it takes time for the solvent to evaporate, inhibiting the instant adhesive properties of α-sia acrylate adhesives, and further When a low boiling point organic solvent is used instead of water as a solvent to promote the evaporation of the solvent, there are various problems such as flammability, toxicity to the human body, deterioration of the working environment, and source of pollution. , solvent-free α-cyanoacrylate adhesive,
This offsets the advantages of non-polluting adhesives. The inventors of the present invention have completed the present invention as a result of intensive studies on how to improve these numerous problems. That is, it is a filler and primer for α-cyanoacrylate adhesives, which is formed by shaping a filler containing a curing accelerator for α-cyanoacrylate. The primer in the present invention is a filler and α-
It consists of a cyanoacrylate curing accelerator (hereinafter referred to as curing accelerator), and an excipient containing a binder and pigment to maintain the solid form of the filler as necessary. Fillers fill and close voids, small pores, and small grooves in the porous adhesive material, prevent penetration of α-cyanoacrylate adhesive, and suppress the occurrence of non-glued areas in the adhesive. Significantly improves adhesive strength. Furthermore, it serves as a diluent for the curing accelerator to prevent workability from being impaired due to excessively rapid set time, and as an aggregate for shaping (molding) the primer. Compounds that can be used as fillers are those that are stable and can be shaped by mixing with a curing accelerator, and that when applied or rubbed onto the surface of the adherend, turn into fine powder on the adherend surface. It is necessary that the material has a so-called sealing effect to fill small holes, small grooves, etc. Specifically, inorganic powders that are difficult to dissolve in water, such as calcium carbonate, gypsum, silica powder, titanium oxide, alumina powder, zinc oxide, powdered calcium sulfite, carbon black, glass powder, diatomaceous earth, silica alumina, and aluminum hydroxide. Alternatively, organic synthetic resin powders such as polyvinyl chloride, polymethacrylate, polystyrene, and cellulose derivatives may be used. When a basic compound is used as a filler, α
-Can also serve as a curing accelerator for cyanoacrylate. The particle size of these fillers is most preferably 1 μ to 150 μ (100 mesh or less) from the viewpoint of filling small grooves, small pores, etc. of the porous adherend. If the particle size is large, it will not be possible to obtain the necessary sealing effect, and if the particle size is small, it will inhibit the wetting of the adhesive and the adherend, making it necessary to apply a large amount of adhesive. There is a tendency that the desired adhesive strength cannot be obtained. The curing accelerator used in the present invention includes α-
The compound is not particularly limited as long as it has the ability to initiate or promote anionic polymerization of cyanoacrylate. Many compounds are known as curing accelerators for α-cyanoacrylate adhesives, all of which can be used. Examples include basic metal hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide, barium hydroxide, calcium hydroxide, magnesium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, barium carbonate. , basic inorganic salts such as sodium borate, tribasic calcium phosphate, tribasic magnesium phosphate, sodium silicate, potassium silicate, metal oxides such as magnesium oxide, zinc oxide, calcium fluoride, calcium chloride, sodium chloride, etc. In addition to inorganic compounds such as inorganic salts and aqueous ammonia, organic compounds such as ethylamine, monoethanolamine, diethanolamine, triethanolamine, 0-phenylenediamine, pentadecylamine, cecylamine, diamylamine, triamylamine, triallylamine, and cyclohexyl Amine, tripendylamine, triphenylamine, dimethyl-p-
Toluidine, diethyl-p-toluidine, dimethylaniline, diethylaniline, N,N-2,4
-Amine compounds such as tetramethylaniline, acid amides such as acetamide, trichloroacetamide, dimethylacetamide, formamide, malonamide, etc., imide compounds such as phthalimide, succinimide, piperidine, tributylphosphine, triphenylphosphine, pyrroline. Organic basic substances such as sodium formate, sodium acetate, calcium acetate, magnesium acetate, sodium acrylate, organic acid salts such as sodium methacrylate, organic acid salt polymers such as sodium polyacrylate, trimethylbenzylammonium chloride, Quaternary ammonium salts such as choline chloride, phosnium salts, and organometallic compounds such as titanates, sodium methoxide, etc. are used. These curing accelerators differ in their ability to initiate polymerization of α-cyanoacrylate depending on their type.
There are some types of α-cyanoacrylate that start polymerization immediately and others that take several minutes to several hours to polymerize, but by appropriately selecting and adjusting the type and amount of α-cyanoacrylate, a primer with an appropriate curing time can be obtained. Among these many curing accelerators, organic amines have a relatively high vapor pressure compared to other inorganic salts, so they evaporate and transpire in the shaped primer, emitting bad odors and Inorganic salts, organic acid salts, and polyorganic salts with low vapor pressure as bases may discolor the adhesive or gel the α-cyanoacrylate adhesive stored in the same place as the primer. Acid salts, quaternary ammonium salts, and the like are particularly effective as curing accelerators for the shaped primer of the present invention. When a compound that can act as a binder, such as water glass or sodium polyacrylate, is used as a curing accelerator, it is not particularly necessary, but it is generally used to collect sealant particles and keep them in solid form. A binder is added to form and solidify. As the binder, water-soluble resins such as polyvinyl alcohol and polyvinylpyrrolidone are most suitable, but other solution-type resins or dispersion-type resins can also be used. Further, the primer can be colored with a suitable pigment or dye to make it the same color as the adherend material and make it less noticeable. The amount of curing accelerator in the primer should be the most appropriate amount depending on the type of curing accelerator, the type and size of the adherend, and the working method, but in general,
0.1% to 90% (by weight) is suitable. When it is less than 0.1%, the accelerating ability is low, and when it is more than 90%, the setting time tends to be too fast and workability tends to deteriorate. There are various methods for obtaining a filler from a filler and a hardening accelerator, and any method may be used. For example, filler powder is added and kneaded into an aqueous solution containing a water-soluble resin such as polyvinyl alcohol as a binder and a hardening accelerator to form a slurry, poured into a suitable mold, air-dried, heated, or forcedly dried. It can be manufactured using It is also possible to manufacture the filler by molding the filler in advance by compression molding or the like, impregnating it with a curing accelerator solution, and drying it. When the hardening accelerator is water-insoluble, a method is adopted in which a mixed slurry with the filler is thoroughly kneaded using a pole mill or the like and then molded. The shape of the excipient in the present invention is not particularly limited, and may include a round bar, a cube, a square bar, a rectangular parallelepiped, a truncated cone, a truncated pyramid, a regular tetrahedron, a regular polyhedron,
Any shape such as spherical or tablet shape is acceptable, but in general, a rod shape is preferred as it makes it easier to apply by hand. The method of applying the primer according to the present invention to a surface to be adhered to is, for example, by rubbing both sides or one side of the surface to be adhered, such as wood, with a filler, rubbing the primer powder into the small holes or grooves of the wood, and then removing the excess. After removing the powder, the α-cyanoacrylate adhesive may be applied, and the two surfaces to be adhered may be immediately pressed together using, for example, fingers or hands. Because the set time is quick, strong adhesion can be obtained by pressing with your hands for a short period of time without having to use a jig to fix it for a long time. The α-cyanoacrylate adhesive in the present invention is (Here, R is an alkyl, alkenyl, cyclohexyl, phenyl, propalkyl group, etc.) The main component is α-cyanoacrylate having a structure,
In addition, it is composed of an anionic polymerization inhibitor such as sulfur dioxide, aromatic sulfonic acid, and sultones, a radical polymerization inhibitor such as hydroquinone and hydroquinone monomethyl ether, and, if necessary, a plasticizer. The low viscosity α-cyanoacrylate adhesive is
It is an adhesive with extremely good permeability, and while it is possible to perform so-called permeation bonding, in which two adherends are brought together and then the adhesive penetrates, it is difficult to bond porous materials such as wood. Conventionally, high molecular weight polymethacrylate resin, cellulose resin,
Penetration has been prevented by using a high viscosity adhesive containing dissolved polyvinyl acetate resin, etc. However, when using a shaped primer as in the present invention, the sealing effect of the sealant and the adhesion due to the curing accelerator are required. Since penetration is significantly suppressed due to the polymerization promoting effect of the agent, good adhesion is possible using a stable and low viscosity adhesive. In addition, α-cyanoacrylate adhesives tend to gradually decrease their adhesion ability during storage, but when the primer of the present invention is used, good adhesion performance is maintained even with adhesives that have been stored for a long time. There are also benefits to be gained. The primer of the present invention can be applied to a wide range of materials such as metals, plastics, and rubber, but the most effective materials include wood, paper, paper products, cloth, leather, and foamed resins. , foam rubber, concrete products, ceramics, ceramics,
There are adherends with porous surfaces such as slate plates, inorganic foams, castings, sintered metals, and foamed metals. Wood, the most typical porous material, is a porous body that is geometrically irregular and has voids of various dimensions, and its surface is composed of incised cell walls with numerous microscopic irregularities, grooves, and pores. There is a lumen shaped like this, and the size of these voids is said to be on the order of several microns or more. Furthermore, the surface contains polar groups such as hydroxyl groups and is usually acidic, so when adhering with α-cyanoacrylate adhesive, a high viscosity adhesive is used and the setting time is slow, so it is difficult to adhere after adhesion. It had to be kept in place for a long time. In addition, polyvinyl acetate emulsion adhesives are commonly used for wood, but adhesive strength is developed only when water, which is a dispersion medium, penetrates and is absorbed by the adherend, so it is hard to set. Thyme varies depending on the type of wood, usually from 10 minutes to several 10 minutes.
It takes a long time, and the water resistance is completely inadequate. The primer method according to the invention provides an extremely fast set time and an excellent water-resistant bond. Normally, the porosity of the wood surface is modified by painting with a filler such as sawdust or coating with a synthetic resin, but the primer of the present invention
It can also be applied to these surfaces. The present invention will be specifically explained below with reference to Examples. The set time and adhesive strength in the examples were measured in the following manner. Set time measurement method: Measurement was performed in accordance with the set time measurement method of the Japan Adhesive Industry Association standard JAI-4 "Testing method for α-cyanoacrylate adhesives." However, the test piece used had dimensions of 12.7 x 12.7 x 38 m/m, and the adhesive surface used was a surface of 12.7 x 12.7 m/m. Measuring method for adhesive strength: Measuring method for tensile adhesive strength according to Japan Adhesive Industry Association standard JAI-4 “Testing method for α-cyanoacrylate adhesives” and JIS K-6852 “Testing method for compressive shear adhesive strength of adhesives” Measured in accordance with ``. however,
All test pieces had dimensions of 12.7 x 12.7 x 38 m/m. When wood is the adherend material, the tensile bond strength is the bond on the surface perpendicular to the grain of the wood (the end), and the compressive shear bond strength. It was created by adhering surfaces parallel to the wood grain (straight grain). Note that the tension or compression speed was 20 mm/min. Example 1 Polyvinyl alcohol powder was added as a binder to 20 g of a 2% by weight aqueous solution of caustic soda as a curing accelerator.
After 0.5 g was added and mixed, 50 g of calcium carbonate powder was added and kneaded, and the mixture was poured into a mold and air-dried at room temperature for 3 days to shape it. When this primer was applied to both adhesive surfaces of the Ezo pine wood test piece, it turned into fine powder on the coated surface, filling small holes and grooves on the surface of the Ezo pine wood, and a so-called sealing effect was observed. A methyl α-cyanoacrylate adhesive (viscosity: 40 cps) was used on this coated surface to determine the set time, tensile adhesive strength, and compressive shear adhesive strength.
At the same time, a test was also conducted without primer treatment.
The results are shown in Table 1.

[Table] By using the primer according to the present invention, the setting time was significantly shortened, and the adhesive strength was also improved due to the sealing effect. If a primer is not used, adhesion is impossible on the cross section of the wood (the adhesion surface perpendicular to the wood grain) seen in the tensile adhesive strength due to penetration of the adhesive. Example 2 As a curing accelerator, 5 g of sodium polyacrylate (manufactured by Toagosei Chemical Industry Co., Ltd., solid content 40%, average degree of polymerization approximately 80), polyvinyl alcohol powder
Add 15g of distilled water to 0.5g, mix, and add gypsum to this.
Add 50g, mix, pour into a mold and mold.
It was dried for 60 minutes and shaped in a constant temperature bath at 150°C. After applying this primer onto the various test pieces shown in Table 2, the set time and compression shear adhesive strength were determined using an ethyl-α-cyanoacrylate adhesive (viscosity 40 cps). As a comparative example, the set time and compression shear adhesive strength were also determined when adhesive was bonded without using a solid primer. The results are shown in Table 2. The solid primer of the present invention can be applied to many other porous materials in addition to various types of wood.

【table】

[Table] Example 3 Trimethylpenzylammonium chloride 1, which is a quaternary ammonium salt, was used as a curing accelerator.
% aqueous solution and polyvinyl alcohol powder
0.5% was added to make a homogeneous solution. As a filler, mix the above solution with 50g of the powder shown in Table 3 until it becomes a slurry of an appropriate viscosity, pour it into a mold, and make a 100g powder.
It was dried at ℃ for 2 hours and shaped. After applying this on a test piece of lauan material, ethyl-α-cyanoacrylate adhesive (viscosity
(20cps) to determine the set time and compressive shear adhesive strength. The results are shown in Table 3.

【table】

[Table] Note that when the filler No. 22 was not added, the primer was used in its liquid state, and after application, it was left to stand for about 60 minutes for the solvent water to evaporate, and then it was bonded.
The compressive shear adhesive strength when adhesive was applied immediately after applying the primer was 30 Kg/cm ² . Example 4 As a filler, 500 g of calcium carbonate and 100 g of a 3% polyvinylpyrrolidone aqueous solution were kneaded, compression-molded, and dried to obtain a solid substance. or ethanol solution) and then dried at 100°C for 3 hours to obtain various excipients. This was coated using lauan material as a test piece, and the set time and compression shear adhesive strength were measured using ethyl-α-cyanoacrylate adhesive (viscosity 100 cps). The results are shown in Table 4.

【table】

[Table] When using only No. 35 filler and not impregnating with curing accelerator, the setting time is extremely slow. Example 5 2 g of various curing accelerator solutions produced in Example 4
2 g of ethyl-α-cyanoacrylate adhesive (viscosity 40 cps) was placed in a polyethylene container containing 2 g of the polyethylene container and stored at room temperature. Similarly, the excipient primer prepared in Example 4 and the ethyl-α-cyanoacrylate adhesive (viscosity
40 cps) in a polyethylene container was placed in the same polyethylene bag and stored at room temperature. After 7 days, 1 month, and 3 months, we observed an increase in the viscosity of the α-cyanoacrylate adhesive, and found that liquid primer No. 27 dimethyl-p-toluidine and No. 28 phenylethylethanolamine The α-cyanoacrylate adhesive was completely gelled in 7 days, and liquid primer No. 29, 2-mercaptopenzimidasole, No. 30 choline chloride, and excipient No. 27 dimethyl-p-toluidine were used. increased the viscosity of the α-cyanoacrylate adhesive within one month, but no increase in viscosity was observed for the other adhesives even after three months. Organic amine curing accelerators with high vapor pressure are α-
It is easier to gel a cyanoacrylate adhesive, and when it comes to liquids and excipients, excipients are less likely to cause α-cyanoacrylate adhesives to gel during storage.

Claims (1)

[Claims] 1. A filler and primer for α-cyanoacrylate adhesives, which is formed by molding a filler containing a curing accelerator for α-cyanoacrylate.