JPH0510155B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for lining a polyurethane elastomer, that is, a method for bonding a polyurethane elastomer to a metal. In the present invention, when a metal surface is lined with a polyurethane elastomer, water resistance and adhesive strength are particularly improved. Cured polyurethane elastomer has mechanical properties,
Because of its excellent wear resistance and oil resistance,
Widely used for belts, solid tires, etc. In particular, recently, taking advantage of its abrasion resistance, polyurethane elastomer has been lined on the inner surfaces of pipes, hoppers, pumps, etc. to prevent steel from abrasion when transporting slurry containing earth and sand during dredging work, mining, etc. things are being done. However, although this lined product has strong adhesive strength in a dry state, when used in the presence of water, the adhesive strength between the polyurethane elastomer and metal decreases significantly, causing the lining to separate from the steel surface.
There was a problem that came to mind. As a countermeasure to this problem, methods have been used in which primers such as phenolic resin and polyvinyl acetal are applied to the surface of the steel, but these methods have not been sufficiently effective. The present inventors conducted various studies with the aim of improving these drawbacks and extending the retention of water resistance strength, and as a result, they arrived at the present invention. That is, in the present invention, a composition consisting of 90 to 60 parts by weight of resol type phenolic resin and 10 to 40 parts by weight of polyvinyl butyral is applied and dried as a primer on a metal surface, and then 10 to 40 parts by weight of resol type phenolic resin is applied on the metal surface.
This is a polyurethane elastomer lining method, which comprises coating and drying a composition consisting of 90 to 60 parts by weight of polyvinyl butyral, and then coating and curing a curable polyurethane elastomer thereon. The resol type phenolic resin used in the present invention is produced by reacting phenols such as phenol, cresol, and butylphenol with aldehydes such as formaldehyde and paraformaldehyde in the presence of an alkaline catalyst such as caustic soda, caustic potash, and ammonia using a known method. It is a mixture of phenol alcohols obtained by Among these phenols, the most preferred compound for the present invention is phenol. The polyvinyl butyral used in the present invention is a compound obtained by reacting polyvinyl alcohol obtained by partially saponifying polyvinyl acetate with butyraldehyde to form butyral. In the present invention, the average degree of polymerization is 600~
1000, a vinyl butyral group content of 75% by weight or more, a residual amount of vinyl alcohol groups of 18 to 22% by weight, and a residual amount of vinyl acetate groups of 3% by weight or less is suitable. In the primer layer of the present invention, the surface in contact with the metal must consist of a layer containing a resol type phenolic resin as a main component, and the surface in contact with the polyurethane elastomer must consist of a layer containing polyvinyl butyral as a main component. Its preferred composition is 90% resol type phenol resin in the layer in contact with the metal.
The layer in contact with the polyurethane elastomer contains 10 to 40 parts by weight of a resol type phenolic resin and 90 to 60 parts by weight of polyvinyl butyral. If the ratio of both is out of this range, the water resistant adhesive strength will decrease. The resol type phenolic resin and polyvinyl butyral of the present invention are used after being dissolved in an organic solvent, if necessary. As a solvent, ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, alcohols such as methanol, ethanol, and isopropanol, esters such as ethyl acetate and butyl acetate, and other solvents such as toluene, xylene, trichlorethylene, and methyl cellosolve may be used alone or in combination. Use by mixing more than one species. The concentration of resol type phenolic resin or polyvinyl butyral in these solutions is preferably 3 to 30% by weight. Moreover, phosphoric acid, P-toluenesulfonic acid, etc. can also be added to this solution as a catalyst. Metals in the present invention include iron, aluminum, brass, copper, bronze, gunmetal, stainless steel, tin, zinc, etc., and these include forged products, cast products, rolled materials, drawn materials, cut materials, etc., and shapes thereof. It may be a round bar, pipe, plate, strip, etc. The polyurethane elastomer of the present invention can be used, for example, in addition to the quick-curing polyurethane elastomer described in JP-A-55-98221, the polyurethane elastomer used in building materials such as flooring materials, waterproofing materials, gland materials, rolls, solid tires, etc. type polyurethane elastomer, etc. Polyurethane elastomers are typically obtained from polyisocyanates and/or polyurethane prepolymers and curing agents that include crosslinking components. As the polyisocyanate and/or polyurethane prepolymer, 2,4-tolylene diisocyanate,
2,6-tolylene diisocyanate, mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate [65/35, 80/20 (weight ratio)] diphenylmethane diisocyanate, Japanese Patent Publication No. 38-4576, etc. Conventionally known aromatic polyisocyanates such as so-called liquid diphenylmethane diisocyanate liquefied by various conventionally known methods, crude products of tolylene diisocyanate, polymethylene polyphenyl polyisocyanate (crude product of diphenylmethane diisocyanate), and cyclohexylmethane. One or a mixture of two or more conventionally known alicyclic polyisocyanates such as diisocyanate and isophorone diisocyanate, and/or these various polyisocyanates, various monomer polyols such as trimethylolpropane, polytetramethylene ether glycol, various Various polyether polyols in which propylene oxide or propylene oxide and ethylene oxide are added to monomer polyols, polycaprolactone polyols, various polyester polyols such as polyethylene adipate, 1,2-polybutadiene polyols, castor oil polyols, and vinyl monomers are gracitated. It is a polyurethane prepolymer with a so-called polymer/polyol.
These prepolymers may be added with colloidal silica or asbestos to impart thixotropic properties. As curing agents, monomer polyols such as ethylene glycol, diethylene glycol, 1,4-butanediol, trimethylolpropane, various polyether polyols, various polyester polyols, various polymer polyols, castor oil polyol, 3,3'-dichloro- A type of aromatic polyamine such as 4,4'-diaminodiphenylmethane or 4,4'-diaminodiphenylmethane, or a liquefied product obtained by dissolving an aromatic polyamine in a plasticizer, various polyether polyols, etc. Or a mixture of two or more types is used. Further, a plasticizer, a filler such as calcium carbonate, a coloring agent, a thixotropic agent, etc. are added to the curing agent as necessary. The method of applying the primer of the present invention is usually 5 to 500 g/m ² (dry coating amount) for the total amount of the first layer and second layer.
Using a primer, it is carried out by commonly known methods such as brush coating, flow coating, spraying, pouring, taping, etc. Also, dry the primer at room temperature or
Perform at 120°C for 0.5-24 hours. In addition, when applying the primer, in order to ensure sufficient adhesive strength, conventional metal surface treatment methods such as degreasing, sandpapering,
It is desirable to use various primers or various chemical treatments. The polyurethane elastomer is applied by a method such as centrifugal press molding, casting, or pouring. The present invention can be applied to linings for the inner surfaces of steel pipes, hoppers, pumps, etc. used for dredging work that requires wear resistance, water-resistant adhesive strength with metal, etc., and for transporting slurry containing earth and sand from mines, etc. Extremely useful. The method for producing the primer, the method for applying the primer, and the method for testing the adhesive strength used in the Examples and Comparative Examples of the present invention will be described below. Primer manufacturing method: Primer A: In a three-necked flask equipped with a stirrer and a reflux condenser, add Denka Butyral #4000-1 (manufactured by Denki Kagaku Kogyo Co., Ltd., polyvinyl butyral resin, average degree of polymerization of approx.
920, vinyl butyral 75% by weight or more) 90g, Plyophene 5010 (manufactured by Dainippon Ink Chemical Co., Ltd.,
170 g of phenolic resin (resol type) and 790 g of a mixed solvent of toluene and isopropanol (1:2 weight ratio) were added, and the mixture was heated and stirred at 60° C. for about 1 hour to obtain a homogeneous solution. Primer B: Using 170 g of Denkabi Tyral #4000-1 and 90 g of Pryoven 5010, the same treatment as Primer A was performed to obtain a uniform solution. Primer C: Using 40 g of Denka Butyral #4000-1 and 220 g of Pryoven 5010, the same treatment as Primer A was performed to obtain a uniform solution. Primer D: Using 220 g of Denka Butyral #4000-1 and 40 g of Pryopen 5010, the same treatment as Primer A was performed to obtain a uniform solution. Primer application method: Apply the primer for the first layer with a brush according to the application conditions listed in Table 1 on an iron plate whose surface has been adjusted to a surface roughness of approximately 50μ (JIS B 0601) using Grittoplast, and leave at room temperature for 30 minutes. After air drying, a second layer primer was applied and air dried at room temperature for 1 hour. The dry coverage of each primer was 10-20 g/ ^m2 . However, when only one type of primer was used, the primer was applied twice. (1) Initial adhesive strength Adhesive test pieces were heated at 25℃ and 55%RH (relative humidity).
After standing for a day, the elastomer was cut into a 25 mm width, and a 180 degree peel test was performed at a pulling speed of 50 mm/min. (2) Water resistant adhesive strength After leaving the adhesive test side at 25℃ and 55%RH for 7 days,
Cut the elastomer into 25mm width and place it in water at 25℃ for 7 days.
The results were obtained by immersing the material for 1 day and performing a 180 degree peel test at a tensile speed of 50 mm/min. Example 1 Primer A was applied as a first layer to an iron plate, and primer B was applied as a second layer. Piprene Q-583 (polyoxytetramethylene glycol/diphenylmethane diisocyanate prepolymer NCO = 15% by weight, manufactured by Mitsui Nisso Urethane Co., Ltd.) and Hyprene MC were placed on the iron plate coated with these primers.
0.004 parts by weight of dibutyltin dilaurate was added to 100 parts by weight of -532 (polyoxytetramethylene glycol/diol-based curing agent manufactured by Mitsui Nisso Urethane Co., Ltd.) and a curing agent with a pot life of about 10 minutes. Two-component polyurethane casting machine (Toho Kikai
AF-206 type), blending ratio 100:66 (weight ratio), discharge amount
Stir and mix at 30g/sec, elastomer thickness is 5
The mixed liquid was discharged so that the thickness was 1 mm. Immediately place the iron plate on which the mixed solution was poured into a curing furnace set at 60℃,
It was cured for 30 minutes to form an elastomer. An adhesion test was conducted on this specimen, and the results were as shown in Table 1. Example 2 After coating the first layer with Primer C and coating the second layer with Primer D, the same treatment as in Example 1 was carried out, and the results were as shown in Table 1. Comparative Example 1 Primer B for the first layer, Primer A for the second layer
After coating, it was treated in the same manner as in Example 1, and the results were as shown in Table 1. Comparative Example 2 Primer B was applied to both the first layer and the second layer,
The results of treatment in the same manner as in Example 1 were as shown in Table 1. Comparative example 3 Primer D on the first layer, 2 primer C on the second layer
was applied and treated in the same manner as in Example 1. The results are as follows.
It turned out as shown in the table. Comparative Example 4 Primer D was applied to both the first layer and the second layer,
The results of treatment in the same manner as in Example 1 were as shown in Table 1.

[Table] Water-resistant adhesive strength can be dramatically improved by applying a primer whose main component is resol-type phenolic resin to the first layer and a primer whose main component is polyvinyl butyral to the second layer. is clear from Table 1.

Claims (1)

[Claims] 1. 90 to 60 parts by weight of resol type phenolic resin and 10 parts by weight of polyvinyl butyral as a primer on the metal surface.
A composition consisting of ~40 parts by weight is coated and dried, and then a composition consisting of 10 to 40 parts by weight of resol type phenol resin and 90 to 60 parts by weight of polyvinyl butyral is coated and dried, and then a curable polyurethane elastomer is applied thereon. A polyurethane elastomer lining method characterized by applying and curing the polyurethane elastomer.