JPS6294335A - Manufacture of pressure sensing type vibration-damping material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for recycling paint waste discharged from a paint factory, particularly to a method for recycling it as a pressure-sensitive vibration damping material.

C) Conventionally, when various industrial products are spray-painted in a painting booth, not all of the sprayed paint adheres to the object to be coated, but some of it does. For example, car bodies that are coated with intermediate and top coats are usually spray painted in a paint booth, and 80-90% of the paint sprayed by a spray gun sticks to the object being coated, but the remaining 10 to 20% of the paint is lost due to scattering in the air.This lost paint is collected by a water shower and collected as paint slag in a slag pond, which is then periodically taken out and buried underground as industrial waste. However, as production volume increases, the amount of paint lost also increases significantly, so there is a problem in securing land for disposal by burial.On the other hand, disposal by incineration Since the paint slag contains a large amount of water, the combustion efficiency is poor and there is a risk of generating undesirable substances such as formalin.
Countermeasures will require huge costs. Under these circumstances, there has been a demand for the development of new techniques for treating unapplied paint, that is, paint scum. However, in recent years, various methods have been proposed for recycling in order to meet such demands.For example, a method of turning paint slag 1 into powder and using it as an additional material for molding materials (Unexamined Japanese Patent Publication No. Showa 32-805
81 Publication), a method of forming a paint by dissolving a grease-like substance obtained by dehydrating paint slag in an organic solvent (Japanese Unexamined Patent Application Publication No. 81-81)
81788), etc., and the present inventors also proposed a method of recycling it into a heat-fusible sheet (Japanese Patent Application No. 3535-9).
No. 17).

(Problems to be Solved by the Invention) However, in the conventional method of recycling paint waste into heat-fusible sheets, the resulting sheets have the following problems. In other words, self-adhesive properties are required as an initial characteristic of heat-adhesive sheets in order to apply them to vertical parts such as car doors and seven-enders, and after manufacturing, self-adhesive properties are often required due to the presence of solvents. However, after a week, it loses its stickiness. This is because the contained solvent evaporates and the paint returns to its original solid state. Also, because it is hard, damping is not necessarily higher than general damping materials.

(Means for Solving the Problems)-' This invention involves blending a filler or a filler and a modifier into paint waste 1 having a solid content of 65% or more, and forming the resulting blend into a sheet. By molding and providing an adhesive layer on one side of this sheet, a pressure-sensitive damping material with good self-adhesion and high damping properties can be obtained.

This is based on the knowledge that

In this specification, "paint waste" refers to unpainted paint generated when spray painting various industrial products such as automobile bodies, electric refrigerators, and electric washing machines, and is usually referred to as paint slag. The main ingredients are pigments, solvents, water, etc.

For example, taking an automobile body as an example, the object to be coated, the car body, is coated with an undercoat by electrodeposition coating or the like, and then an intermediate coat and a top coat are coated by a spray coating method in a paint booth.

Therefore, paint sludge is broadly classified into single-color intermediate paint sludge, multicolored top-coat paint sludge, and paint sludge that is a mixture of the two.

The composition of these paint slags varies slightly depending on the type of paint used, but this is the general outline! The resins include alkyd resins, acrylic resins, melamine resins, epoxy resins, etc., and the pigments include inorganic pigments such as titanium oxide, carbon black, talc, and clay, and phthalocyanine, azo, and quinacridone pigments. Examples of solvents include aromatic hydrocarbons such as toluene and xylene, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, alcohols such as ethanol, isopropanol and butanol, and ethyl acetate. , ester-based solvents such as isopropyl acetate and butyl acetate, and glyfur-based solvents such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, and ethylene glycol monomethyl ether, and contain water in various proportions. . Next, an example of paint sludge collected from a paint sludge pond is as follows.

Resin content 80% by weight Pigment content 2 IS weight% Solvent
Minutes: 20% by weight Moisture: 25% by weight The method for producing the pressure-sensitive vibration damping material of the present invention basically involves blending fillers, modifiers, etc. into paint slag with a solid content of 65% by weight or more. step, a sheeting step of forming the obtained blend into a sheet shape, and a step of providing an adhesive layer. Paint slag that has just been taken out of a slag pond usually contains a large amount of moisture and is non-uniform. Therefore, in such a case, any method such as centrifugal dehydration, hydrodehydration, pul dehydration, kneader dehydration, hot air dehydration, or infrared dehydration can be used.
It is dehydrated so that the solid content is 65 inches or more. Hard 1
-) If the fraction is less than 61i%, the moisture remaining in the molded sheet may cause foaming during heat-sealing, which is undesirable. Another example of a modifier is a liquid resin, and when blending this resin, it is necessary to know the solid content of the paint slag in advance, but since the water content is not homogeneous, there is a large measurement error. From this point of view as well, the solid content in the paint slag is preferably 65 inches or more.

The liquid resins used as fillers and modifiers are selected and blended according to the sheet properties, ie, prevention of drooping, imparting flexibility, uniformity of color tone, cost reduction, etc. The filler may be an inorganic filler or an organic filler. Examples of inorganic fillers include titanium oxide, clay, talc, silica, red iron, etc., and organic fillers include polyethylene, polypropylene, phenol, etc. Examples include powder and fiber. The amount to be added is up to 500 parts by weight per 100 parts by weight of the solid content of the paint slag. Furthermore, paint slag is a mixture of various paints, and the color tone of the product is not necessarily constant.

Therefore, if necessary, carbon black or a dark pigment can be added to unify the color tone.The liquid resin of the modifier is added when imparting flexibility to the molded sheet. Liquid resins include polybutadiene resins, phenol resins, xylene resins, epoxy resins, and polyamide resins, and those that are liquid at room temperature and have a molecular weight of 200 to 2000 are preferred.

It is effective to add 4 parts by weight or more to 100 parts by weight of the solid content of the paint slag, and a range of 4 to 800 parts by weight is preferable.

The formulation of these materials is done by adding the materials to the paint slag that has been dehydrated as necessary to a specified solid content, and then uniformly dispersing and kneading it using a U-Tor, mixer, kneader, or other kneading machine. Do by doing.

Sheeting is a process in which the kneaded material obtained in the above blending step is formed into a sheet with a predetermined thickness using a roll or other molding machine.

Next, the process of providing the adhesive layer on the sheet surface will be described in detail.

The first purpose of attaching the adhesive layer to one side of the molded sheet is to provide self-adhesive properties so that it can be used in vertical areas, and the second purpose is to increase the vibration damping function. That is, the selected adhesive is a permanent adhesive that does not change over time, and can be applied regardless of the state of the vibration damped object, such as a vertical portion. Further, in the pressure-sensitive damping material obtained by the method of the present invention, 1. The molded sheet using paint slag functions as a restraining layer, and the adhesive layer functions as a viscoelastic layer that converts vibration energy into heat. Due to the presence of the constraining layer, the adhesive undergoes the original bending deformation and shear deformation, so
Absorption of vibration energy is increased and high damping properties are exhibited.

Adhesives include butyl rubber, acrylic, and the like. Applying a solvent or emulsion solution,
Let it dry or apply an adhesive layer to one side of the laminate and constraint layer. Application is done by spraying or coating, and the dry thickness is Is~500, preferably 2ONls00.
The range is μ.

The pressure-sensitive vibration damping material produced by the method of the present invention has a thickness of 1 to 6 mm, preferably 2 to 4 mm, and its main purpose is vibration damping and sound insulation of articles, and it can be used for automobile bodies.

For example, it can be applied to doors, fenders, roofs, etc. inside cars, and it can also be used as a soundproofing material for buildings and other items.

(Example) This invention will be explained below with reference to Examples and Comparative Examples.

In the examples, adhesion retention and damping properties for vertical portions were evaluated by the following method.

(b) Adhesion retention for vertical parts A vibration damping material □ with a width of 40 mm and a length of 100 mm is pasted approximately in the center of the surface of an electrocoated plate with a width of 80 mm and a length of 200 mm, and a damping material □... is placed in a drying oven for a long time. Suspend vertically in the horizontal direction for vibration damping; use the lower side of the material as a marked line, heat it at 140°C for 80 minutes, measure the deviation distance from marked line A, and pass if the deviation is within 101111.

(b) Width 101 with the upper part fixed with a fixture using the damping cantilever resonance method
A damping material measuring 10 mm wide x 220 mm long was pasted on the surface of a steel plate measuring 11 mm x 260 mm long x 1 mm thick, and using a vibration exciter below,
Secondary resonance frequency f. The half value width is measured, and the loss coefficient η is determined from the following equation to evaluate the damping I...ng.

Quick Example 1 Paint Mixed synthetic resin paint slag (solid content 40-50% by weight) of acrylic and alkyd systems recovered from crude oil was kneaded for 20 minutes on a roll machine, dehydrated, and turned into a pink clay-like material with a solid content of 82% by weight. Paint slag was obtained. The composition of this paint slag was 48% by weight resin and 84% by weight pigment. To this dehydrated paint slag, 150 parts by weight of talc (manufactured by Kunimine Kogyo Co., Ltd., trade name: Talc GT) with an average particle size of 40 to 50 μm was added to 100 parts by weight of the solid content of the paint slag, and the mixture was mixed with a kneader to approx. The mixture was kneaded for a minute and then formed into a sheet with a thickness of 2 mm using a press. This molded sheet was coated with an acrylic adhesive in an emulsion state (trade name: Cypinol AT-14, manufactured by Saiden Chemical Co., Ltd.).
NT) was applied to a thickness of 80μ using a bar coater, then dried at 100°C for 80 minutes, and non-adhesive paper was pasted on the adhesive 1 to obtain the pressure-sensitive vibration damping material shown in Figure 1. Ta. 1st
In the figure, 1 is the paint slag compounded sheet, 2 is the adhesive, and 8
indicates non-adhesive paper. And the thickness of the adhesive after drying is 40
It was ~45μ. Adhesive retention and damping in vertical positions were measured using the above evaluation method, and good results were obtained as shown by track 1]1 in Table 1 and Figure 2.

Example 2 An epoxy resin (manufactured by Yuka Shell Epoxy Co., Ltd., trade name: Ebi□゛) was added to a pink clay-like paint slag with a resin content of 48% by weight and a pigment content of 84 layers obtained in the same manner as in Example 1. Co) 828
) to 100 parts by weight of the solid content of the paint slag and 20 parts by weight of talc (manufactured by Kunimine Kogyo Co., Ltd.) with an average particle size of 40 to 50 μm.
80% (trade name: Talc GT) per 100 parts by weight of paint slag
A pressure-sensitive damping material having a thickness of 21 m and an adhesive layer of 40 to 45 μm was obtained by the same procedure as in Example 1.

Next, the same evaluation as in Example 1 was carried out, and the adhesion retention for vertical parts was shown in Table 1, and the damping property was shown in Curve 2 in Figure 2.
Good results were obtained as shown in . In addition, the sheet had flexibility due to the effect of blending the liquid resin, and the initial sheet properties were also good.

Comparative Example 1 A pink clay-like paint slag with a resin content of 48% by weight and a pigment content of 84% by weight obtained in the same manner as in Example 1 was coated with an average particle size of 40 to 5%.
50 parts by weight of 0μ talc (manufactured by Kunimine Kogyo Co., Ltd., Trade 1, product name Talc GTA) was added to 100 parts by weight of the solid content of the paint slag, kneaded for 26 minutes in a kneader, and then kneaded with a press to form a 2-inch thick self-adhesive layer. A flexible sheet was formed. Adhesion retention and damping properties for vertical portions were measured 2 using the same evaluation method as in Example 1, and the results shown in Table 1 and curve 8 in FIG. 2 were obtained. 1 damping had almost the same performance, but the adhesive retention was poor and it could not be used for vertical parts.

Comparative Example 2 The damping material has the same structure as the damping material shown in Fig. 1, but the adhesive layer is made of asphalt as the main component.
Co., Ltd., trade name: PA Melsheet) was evaluated for adhesion retention and damping properties in vertical positions in the same manner as in Example 1, and the results shown in Table 1 and Curve 4 in FIG. 2 were obtained. Similar to Comparative Example 1, Mouse... has good damping properties, but it drips when heated and cannot be used in vertical locations.

(Effect of the invention) As explained above, the pressure-sensitive control of the present invention.

The method for manufacturing the vibration material is to mix paint waste with a solid content of 65% by weight or more with a certain amount of filler or a filler and a modifier, form the resulting mixture into a sheet, and apply one side of the sheet. By adding an adhesive to the material, the vibration damping material has a higher performance and the paint waste becomes more pressure sensitive.

This product responds to the strong social demand for the recycling of industrial waste by converting it into molded vibration damping materials, and greatly contributes to the effective use of resources.

[Brief explanation of drawings]

FIG. 1 is a perspective view of the pressure-sensitive damping materials prepared in Examples, and FIG. 2 is a curve diagram showing the damping properties of the damping materials of Examples 1 to 9 and Comparative Examples 1 to 2. 1...Paint slag compounding sheet 2...Adhesive 8...Non-adhesive paper 1

Claims (1)

[Claims] 1. 50 to 500 parts by weight of a filler is blended with paint waste having a solid content of 65% by weight or more per 100 parts by weight of the solid content, and then the resulting mixture is applied to a sheet. 1. A method for producing a pressure-sensitive vibration damping material, the method comprising forming the sheet into a sheet and providing an adhesive layer on one side of the sheet. 2. Claim 1, in which 4 parts by weight or more of a resin having a molecular weight of 200 to 2000 and which is liquid at room temperature is further added as a modifier to the above paint waste per 100 parts by weight of its solid content.
A method for producing a pressure-sensitive vibration damping material as described in .