JPH02265931A - Surface treatment of molding - Google Patents

Abstract

PURPOSE:To improve the adhesion of a molding containing a propylene polymer to a coating material by treating a molding containing at least two specified propylene polymers with wave energy in an organic solvent containing a primer for polypropylene. CONSTITUTION:A process for surface-treating a molding of a composition containing at least two propylene polymers with wave energy having a frequency of 15-50kHz in an organic solvent containing a primer for polypropylene, wherein either of the propylene polymers comprises a propylene homopolymer (PP) having (A) a xylene-soluble component of at most 5.0wt.% at a temperature of 30 deg.C or a propylene/ethylene random copolymer (PER) of an ethylene comonomer content of at most 10wt.%, and the other comprises an ethylene/ propylene random copolymer (EPR) having (B) a xylene-insoluble component of at most 5.0wt.% at 30 deg.C and a propylene comonomer content of 35-75wt.%, and the rate of EPR amounting to the total of PP, PER and EPR, the primer, the organic solvent, etc., are specified.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for surface treating a molded article of a composition containing at least two types of propylene polymers. More specifically, the t! ! The present invention relates to a surface treatment method that can significantly improve II property. [Prior art l] As is well known, propylene polymers (propylene homopolymers, copolymers containing propylene as the main component) not only have excellent moldability, but also have excellent mechanical properties, moldability, and solvent resistance. Because it has good properties such as oil resistance and chemical resistance, it is manufactured in large quantities industrially and is used in a wide range of industrial parts and daily necessities such as automobiles, electrical appliances, and electronic equipment. However, because propylene polymers do not have polar groups in their molecules (so-called non-polar), they do not have good adhesion to polyurethane. There are various problems. - As an example, a widely used automobile bumper will be explained. Conventionally, bumpers made of metal or polyurethane have been widely used. In recent years, with the aim of reducing the weight and cost of automobiles, bumpers manufactured from propylene-based polymers or compositions containing propylene-based polymers as a main component have been widely used. This bumper is for your vehicle!
When wearing A, the surface of the molded item is textured in advance,
There are many cases in which it is used without painting, but in order to bring out a more vivid and luxurious feel, there are many cases in which the bumper is painted with polyurethane-based φhui and then installed on the vehicle, and this tendency is This is further increasing as automobiles become more upscale. However, since the propylene polymer mentioned above does not have a polar group in its molecule, it is a chemically extremely inactive polymeric substance. For this reason, when painting polyurethane, the molded product is generally coated with electrical treatment (
For example, corona discharge treatment method, plasma treatment method), 11
1 Mechanical roughening method. Moldings are commonly treated by surface treatment methods such as flame treatment and oxygen or ozone treatment. Furthermore, prior to these surface treatments, it is recommended that one surface be cleaned in advance with a solvent such as alcohol or aromatic hydrocarbon. It is also known to immerse the molded article in organic solvents such as 1,1.1-trichloroethane, perchlorethylene, pentachloroethylene and toluene at temperatures close to their boiling point or to expose them to the vapors of the organic solvent. [For example, see Kenyuki Takagi, lti, Heizo Oki, ed., “Plastic Materials Course ■, Polypropylene Resin” (published by Nikkan Kogyo Shimbun, May 1960), pp. 216 to 219], However, in these methods,
In both cases, not only a processing device is required, but also a considerable amount of time is required for the processing. Therefore, before applying polyurethane coating to a molded product (bumper) manufactured from a 5-propylene polymer or a composition containing a propylene polymer as a main component, the surface of the molded product is degreased using an inert organic solvent. After the solvent is almost completely removed by evaporation, etc., a primer capable of adhering to propylene-based polymers and polyurethane must be applied to the surface, and a process must be performed to ensure almost complete adhesion (baking) of the primer. This process takes a long time.
! m (usually about 40 to 80 minutes). Therefore, manufacturing bumpers made of propylene polymer coated with polyurethane requires a long coating cycle, which not only makes mass production difficult but also increases costs. Furthermore, the complicated painting process is also a factor contributing to poor yields. 1. Propylene polymers or their compositions, which are normally used in bumpers, are coated with ultraviolet absorbers to enhance weather resistance. Stabilizers such as heat stabilizers and antioxidants are used in combination in arbitrary formulations.However, after several years of actual driving, the surface of the molded product (bumper) changes color. Chalking or crabbing may occur.2 The current bumper grades are not sufficient, and the use of bumper grades with better weather resistance will increase as cars become more luxurious and in regions with harsh climates. Therefore, as a countermeasure, it may be possible to increase the amount of conventional weather-resistant formulations or add new additives, but simply increasing or adding these ingredients may cause problems with appearance during molding. (for example, uneven gloss or whitening on the surface), additives increased or added to the surface of the molded product after molding may bleed, deteriorating the appearance, and long-term use during actual running. There are various problems such as whitening of the surface. For these reasons, some of the inventors of the present invention have proposed that the propylene polymer has at least one unsaturated bond in the molecule,
Moreover, a composition in which a modified propylene polymer obtained by treating an organic compound containing a hydroxyl group in the presence of an organic peroxide is blended with a propylene polymer can be used as a polyurethane paint without using a primer. We have previously proposed paintable propylene polymer compositions (e.g., JP-A-61-272255, JP-A-62-62-1).
No. 64848, No. 62-119243, No. 62-20
No. 7344). The compositions of these inventions exhibit satisfactory adhesion to some polyurethane paints even without the use of a primer. However, other polyurethane paints do not necessarily exhibit satisfactory adhesion.

Problem to be Solved by the Invention J As mentioned above, when coating polyurethane on the surface of a molded product made from a composition containing a propylene polymer, the molded product is generally coated with an industrially produced organic solvent. After the surface has been degreased and dried, a primer is applied and dried, and then polyurethane is applied.
It is an object of the present invention to establish a method that eliminates one of the steps and has the same degree of adhesion between the molded article and the polyurethane as the coated article obtained by this step. [Means and effects for solving 81 problems 1 According to the present invention, these problems are solved. This is a method in which the surface of a molded article of a composition containing at least two types of propylene polymers is treated with wave energy having a frequency of 15 to 50 Kflz in an organic solvent containing a primer for polypropylene. home. (A) One is a propylene homopolymer with a xylene soluble content of at most 5.0% by weight at a temperature of 30°C, or a propylene-ethylene random copolymer with an ethylene copolymerization ratio of at most 10% by weight. and (B) the other has a xylene insoluble content of at most 5.
0% by weight, and the copolymerization ratio of propylene is 35~
75% by weight of the ethylene-propylene random copolymer in the total amount of the propylene homopolymer, propylene-ethylene random copolymer and ethylene-propylene random copolymer. The composition ratio is 5.0 to 40% by weight, and the melt index, Z, r, J
Measured according to Is K7210 with 1 condition 14,
(Hereinafter referred to as rM I J) Ha2.0~100g/1
The primer is a one-component primer that has a functional group capable of bonding with a compound having an isocyanate group and can form a film on the surface of a molded product, and the organic solvent has a melting point of 20°C or less. and the boiling point is 50°C or higher,
A method for surface treating a molded article, which is characterized in that it is capable of dissolving a diethylene-propylene random copolymer, and is chemically inert to all polymers and primers. It can be solved by The present invention will be specifically explained below. IA) Propylene homopolymer and propylene-ethylene random copolymer The propylene homopolymer used in the present invention is obtained by homopolymerizing propylene. The propylene-ethylene random copolymer is obtained by copolymerizing propylene with at most 10% by weight (preferably 730% by weight or less, preferably 5.0% by weight or less) of ethylene. be. These propylene homopolymers and propylene-ethylene random copolymers each contain at most 5.0% by weight (preferably 3.0% by weight or less) of a component that is soluble in xylene at a temperature of 30°C. It is something. Furthermore, the MI of these polymers generally ranges from 2.0 to log
/10 minutes, preferably 5.0 to 100 g/10 minutes, and particularly preferably 5.0 to 50 g/10 minutes. When Ml of propylene homopolymer stone and propylene-ethylene random copolymer is less than the lower limit, +11
The tightenability is not good, and the moldability of the composition is also not good. On the other hand, if the upper limit is exceeded, the impact resistance of the composition is not good. +8) Ethylene-propylene random copolymer The copolymerization ratio of propylene in the ethylene-propylene random copolymer used in the present invention is 35 to 75% by weight.
and preferably 35 to 70% by weight, especially 40 to 70% by weight.
70% by weight is suitable. The copolymerization ratio of propylene is 3
If an ethylene-propylene random copolymerization ratio of less than 5% by weight is used, the impact resistance of the composition will be poor. On the other hand, a propylene-propylene random copolymer in which the copolymerization ratio of propylene exceeds 75% by weight is not only difficult to manufacture (there is a problem in terms of the rigidity of the composition). The polymer contains at most 5.0% by weight (preferably 4.5% by weight or less) of a component that is incurable to xylene at a temperature of 30°C.
For the same reason as in the case of propylene homopolymer and propylene-ethylene random copolymer described in I Ltliii, it is usually 1.0-100 g/10 min, and 5.0 g/10 min.
~80g/10 minutes is desirable, especially 5.0~70g
/10 minutes is suitable. These propylene homopolymers, propylene-ethylene random copolymers, and ethylene-propylene random copolymers are produced by homopolymerization and copolymerization, respectively, to form the composition of the present invention! IJ j3 may be mixed in the composition ratios listed below, or the propylene homopolymer and/or propylene-ethylene random copolymer may be prepared in advance and the catalyst system used in the production of these polymers and polymers may be used. It may be produced by so-called block copolymerization in which ethylene and propylene are copolymerized in the same polymerization vessel or in separate polymerization vessels in the presence of . In any of the above cases, M of the total amount of propylene homopolymer and/or propylene-ethylene random copolymer and ethylene-propylene random copolymer
K is 2.0-100g/10min, 5.0-50g
/10 minutes is preferable, especially 5. θ~50g/10
minutes is preferred. If the Ml of the total amount of propylene alone and/or propylene-ethylene random copolymer and ethylene-propylene random copolymer is less than 2.0 g/10 min, wire crosstalk and moldability of the composition are poor; ,
If foOg/10 minutes is exceeded, the mechanical properties of the composition, particularly the impact resistance, will be poor. The content of ethylene in the total amount of these polymers is generally 3.0 to 30% by weight, preferably 5.0 to 30% by weight, especially 5.0% by weight, in terms of monomer units.
~25% depreciation is preferred. If the content of ethylene in the total amount of these polymers is less than 3.01 li% as a heptad unit, there is a problem in the impact resistance of the composition. On the other hand, if the amount exceeds 30%, there is a problem in terms of the rigidity of the composition. When producing the composition of the present invention, the rigidity of the composition can be improved by incorporating an inorganic filler. Furthermore, the illumination resistance of the composition can be improved by blending the ethylene-propylene rubber described later. Ic) Inorganic filler The inorganic filler used in the present invention is generally one widely used in the fields of synthetic resins and rubbers. The inorganic filler is preferably an inorganic compound that does not react with oxygen or water, and that does not decompose during crosstalk or molding. Aluminum is used as an inorganic filler. Oxides of metals such as copper, iron, lead, nickel, magnesium, calcium, barium, zinc 4-zirconium, molybdenum, silicon, antimony, and titanium, their hydrates (hydroxides), sulfates, and carbonates. It is broadly classified into salts, compounds such as silicates, double salts thereof, and mixtures thereof. Applicable! ! Representative examples of fillers III are described in Japanese Patent Application No. 59-8535. Among these inorganic fillers, those in powder form have a diameter of 3
Those in the form of fibers preferably have a diameter of 1 to 500 ua (preferably 1 to 300 µl) and a length of 0.1 to 6 m (preferably 1 to 300 µl). 0.1 to 5 Il■) is preferable, and flat plate-shaped ones have a diameter of 30μ or less (preferably 10μ or less).
Preferably. Among these inorganic fillers, those in the form of flat plates (flake) and those in the form of powder are particularly suitable. Suitable inorganic fillers include talc, mica, silica, glass fiber, graphite, and the like. +01 Ethylene-propylene rubber Furthermore, the ethylene-propylene rubber used in the present invention is an ethylene-propylene copolymer rubber obtained by copolymerizing ethylene and propylene, and ethylene and propylene as the t component, and 1 , 4-pentadiene, 1,5-hexadiene and 3,3-dimethyl-1,5-hexadiene. Linear or branched diolefins or bicyclo[2,2,11-
Ethylene monomer units of multicomponent copolymer rubber obtained by copolymerizing monomers such as cyclic diene hydrocarbons such as heptene-2 and its derivatives (generally not more than 10% by weight): The weight ratio of propylene monomer units is usually 30:70 to 80:20.
preferably 40:60 to 75
:25 is suitable. These ethylene-propylene rubbers are produced by copolymerization or multicomponent copolymerization of catalytic ethylene obtained from transition metal compounds and organic aluminum compounds, and propylene, or ethylene, propylene, and the above monomers. Muny viscosity (M
L, , (100°C) 1 is 10-140, 15-1
A number of 120 is desirable, and a number of 30 to 110 is particularly preferred. If an ethylene-propylene rubber with a Mooney viscosity of less than 10 is used, moldability will improve, but l
Not only is the effect of improving impact resistance low, but layer peeling may occur during gate cutting of a molded product, which may cause trouble. On the other hand, if a material exceeding 140 is used, not only will it be difficult to disperse during kneading, but
Even if a uniform composition is obtained, flow marks, weld lines, and the like become highly visible on the surface of the molded product, making it impossible to obtain a molded product with a good appearance. fE) Composition ratio In the composition of the present invention, the composition ratio of the ethylene-propylene random copolymer to the total amount of the propylene homopolymer, the propylene-ethylene random copolymer, and the ethylene-propylene random copolymer is 5. 0-4
It is 0 overlay %. 5.0 to 35% by weight is preferred, and 7.0 to 30% by weight is suitable. If the composition ratio of the ethylene-propylene random copolymer to the total amount of these polymers is less than 1% of 5.0 mm, the resulting composition will have poor 11I impact resistance. On the other hand, if it exceeds 40% by weight, the stiffness of the composition will be poor. When compounding ethylene-propylene rubber, the proportion of this rubber in the composition is generally at most 30% by weight, preferably 3.0 to 30% by weight, particularly 5.0% by weight.
~30% by weight is suitable. If the proportion of ethylene-propylene rubber in the composition exceeds 30%, the impact resistance of the composition, especially at low temperatures, may deteriorate (4).
Although the impact resistance is good, other mechanical properties (eg, stiffness, tensile resistance) are poor. In addition, when blending an inorganic filler, the j
The composition ratio of the machine filler is usually at most 30% by weight.
, and 1% of 1.0 to 30 balls is desirable. In particular, 1.0 to 2511% is preferable. If the composition ratio of the inorganic filler in one composition exceeds 30%, the moldability may be poor and the impact resistance, especially at low temperatures, may deteriorate. is not good. iF) Production of the composition To produce the composition of the present invention, use of the composition for the propylene homopolymer and/or propylene-ethylene random copolymer and ethylene-propylene random copolymer or these polymers is required. Depending on the purpose, the inorganic filler and/or ethylene-propylene rubber may be mixed to make it uniform.In this case, as described above, propylene homopolymer and/or propylene-ethylene random copolymer and ethylene- The propylene random copolymer may be produced by so-called block J'-1 polymerization, or separately produced products may be mixed at this stage. It is of course possible to add additives such as oxygen, light or heat stabilizers, fi oxidation inhibitors, processability improvers, lubricants, antistatic agents and pigments. The composition may be triblended using mixers such as tumblers, ribbon blenders, and Henschel mixers, or may be triblended using mixers such as tumblers, ribbon blenders, and Henschel mixers, or in batch mixers (e.g., Banbury mixers) or continuous mixers (e.g., Banbury mixers). For example, mixing can be carried out using an extruder (extruder), but it is also possible to mix continuously using a continuous mixing machine as described above. Moreover, more uniform mixing can be achieved by using these methods in combination (for example, by triblending and then continuously mixing the mixture). (G) Molding method The composition thus obtained is usually molded into a pellet shape, and the desired molded product is formed by molding methods such as injection molding and extrusion molding that are commonly used in the respective fields of thermoplastic resins. Manufactured in Even when melt-kneading is performed when producing the above composition,
Even when molding, the temperature is higher than the melting point of the polymer used, but at a temperature that does not cause thermal decomposition. For these reasons, the temperature is generally 180 to 280°C (preferably 200 to 280°C).
60°C). The present invention can be achieved by treating the surface of the thus obtained molded article with wave energy having a frequency of 15 to 50 Kf (Z) in an organic solvent containing a primer for polypropylene. ( [f) Primer for polypropylene The primer for polypropylene of the present invention is a one-component primer that has a functional group capable of bonding with a compound having an isocyanate group and can form a film on the surface of the molded article. The groups include hydroxyl group (-OH), carboxyl group (-COOJl), its anhydride group, and amino 1 (-N
! -1□), and the resin J component in the primer is one that has an affinity with polypropylene resin, and the primer is a polypropylene grafted with chlorinated polypropylene and an unsaturated carboxylic acid or its anhydride. can give. The primer is generally commercially available as a one-part type dissolved or suspended in a V@can. (The organic solvent used in the Jll-soluble solvent invention has a melting point of 20°C or lower (preferably 10°C or lower, preferably 0°C or lower),
If a solvent with a boiling point of 50°C or higher (preferably 60°C or higher, preferably 70°C or higher) and a melting point of higher than 20°C is used, it will be in a solid state at room temperature, making it difficult to handle. There's a problem. On the other hand, if an organic IS having a boiling point lower than 50° C. is used, evaporation (volatilization) will increase during use or storage, which is not preferable. In addition, the organic solvent is one that makes the ethylene-propylene random copolymer soluble (1).
If an organic solvent that does not dissolve the propylene random copolymer is used, the 11-pus peel strength after coating will not be sufficient. However, note that the organic solvent is one that does not substantially dissolve or swell either the propylene homopolymer or the propylene-ethylene random copolymer in the molded article 5 in the surface treatment described below. On the other hand, if an organic solvent that dissolves or swells these polymers is used, even if a molded article with an excellent shape is produced as described above, the shape of the molded article cannot be maintained by this treatment. The primer and the organic solvent are all inert propylene homopolymers, propylene-ethylene random copolymers, and ethylene-propylene random copolymers. On the other hand, if the primer and organic solvent are active against these polymers, reactions may occur during the surface treatment described later, which is not preferable. For these reasons, representative examples of the 41 solvents used in the present invention include chlorinated aliphatic hydrocarbons, chlorinated fat hydrocarbons, and aromatic hydrocarbons having the above melting point and boiling point range. Among them, chlorinated aliphatic hydrocarbons are preferred, and 1,i,1-1-lychloroethane is preferred. In performing the surface treatment described below, the mixing ratio of the primer in the organic solvent is generally 5 to 90% by weight, but a lower concentration is more advantageous in terms of cost. For this reason, 5-20% insect weight is preferred, especially 5-1%
5% by weight is preferred. (K1 Surface treatment To treat the surface of the molded product obtained as described above, the molded product is immersed in a solution obtained by dissolving the polypropylene primer in an organic solvent obtained in the above manner. can be achieved by processing wave energy (ultrasonic waves) of 15 to 50 KI (z). At this time, it is generally carried out at room temperature. There is no need to intentionally carry out the process in a heated or cooled state. The molded product whose surface has been treated can substantially completely dry the adhering organic solvent without deforming the molded product.This drying is not done by any special method, but by a normal drying process after applying the primer. This can be achieved by doing the same thing as above. In this way, wave-like patterns of primer are formed on the surface of the molded product, and the adhesion between the surface and, for example, a polyurethane paint is significantly improved. 1 Effect] This book Although the mechanism of the development of RI film adhesion by the surface treatment of the invention is not clear, it is presumed to be due to the following mechanism of action. As a result of the above surface treatment, the surface of the molded product becomes isocyanate. A wave diaphragm is formed by a primer having a functional group capable of bonding with a compound having a 1.1 group.As a result, a strong adhesion is developed between, for example, a polyurethane paint and the object to be diaphragm.On the other hand, when molded using an organic solvent, After the ethylene-propylene random copolymer near the surface of the object swells,
A primer in an organic solvent is combined with a molecular chain of ethylene-propylene random copolymer and Vande Waals (Vande).
r maal, s ) By diffusing within the range of the force, a strong adhesion force is developed between the surface of the molded product and m*. Furthermore, the wave energy has the advantage of promoting the diffusion of the primer along with the swelling of the ethylene-propylene random copolymer by the organic solvent. 1 Example and Comparative Example] The present invention will be further explained below with reference to Examples. In the Examples and Comparative Examples, the coating film adhesion strength was determined by making a lea-width streak on a molded flat plate and increasing the tensile speed. 505m
It was determined by measuring the 180 degree peel strength of the coating film under conditions of /min. Also, the flexural modulus is ASTM D7
The Izot impact strength (notched) was measured according to ASTM No. 0256 and the temperature was 23
℃ and -40℃. Furthermore, the heat distortion temperature was measured according to A+77M D648. In addition, the production and physical properties of propylene polymers, amorphous ethylene-propylene copolymers, and inorganic fillers that are substantially composed of propylene homopolymers and ethylene-propylene random polymers used in Examples and Comparative Examples, etc. Shown below. 1 (A) Propylene-based polymer 1 As a propylene-based polymer, only propylene was polymerized in a polymerization vessel using a Ziegler-Natsuta catalyst without using a solvent. Then, ethylene was supplied to this polymerization vessel to produce a random copolymer of ethylene and propylene. Obtained propylene-based monomer

[rPP (hereinafter referred to as AIJ) is an ethylene-propylene random copolymer containing 75% by weight of propylene homopolymer (insoluble in xylene at a temperature of 30°C) and 50% by weight of ethylene. (soluble in xylene at a temperature of 30°C).The Ml of this PP(^) was 13
g/10 minutes. [(B) amorphous ethylene-propylene copolymer monomer,
As an amorphous ethylene-propylene copolymer, an amorphous ethylene-propylene copolymer having a Mooney viscosity (ML, 1100°C) of 35 (copolymerization ratio of propylene 27 times, hereinafter r EP) f (referred to as J) was used. [(C) Inorganic filler l Furthermore, as an inorganic filler, talc having an average particle size of 2.0 μ■ was used. Examples 1 to 4 The formulations shown in Table 1 The indicated amounts of PP (A1.EPR and talc were pre-triblended for 5 minutes using a Henschel mixer.The resulting mixtures were mixed using a twin-screw extruder (diameter 30m++m) at a resin temperature of 200°C.
A pellet-like composition was manufactured while mixing wires (Examples 2 to 4). Each of the pellets thus obtained and the pellets of PP(^) were molded at a resin temperature of 230°C,
Samples were prepared for measuring Izot impact strength, 2 flexural modulus, and heat deformation temperature. In addition, a convex pellet was injection molded in the same way, and the thickness was 0.2 m.
A sample of l+ (13 cm x 23 cm) was molded. Each written plate was coated with primer (manufactured by Nippon BB Chemical Co., Ltd., trade name RBI50-1) 1, 1, 1. containing IO weight ff1%. The sample was immersed in -1-lichloroethane solution and subjected to wave energy treatment (ultrasonic treatment) for 60 seconds under condition F where one round tfIin was 36KIIzj; rotation output force IOOOW. Then, it was dried at a temperature of 80° C. for 45 minutes to almost completely volatilize the l,l,l-)lychloroethane. A two-component urethane paint (manufactured by Nippon BB Chemical Co., Ltd., trade name: Nippon BB Chemical R271 Pure White) was applied to each of the treated surfaces by spraying it uniformly once. In this way, the coating VA adhesion strength of each sample was measured. In addition, the IZO! impact strength 1 bending elastic modulus and heat deformation resistance temperature at 23°C and -40°C were measured. It is shown in Table 1. (The following is a blank space) Actual Example H1 5-1O5 Comparative Example A pellet-like composition was prepared in the same manner as in Example N4.
ton), the resin temperature is 230'C, the thickness is 4+ms, the length is 1500cm @ and the width is 3:30.
I made a bumper for the Cats in 1953. i'# from 8 bumper I 0caX I 5ci
Sample J1 of w was cut out and the content (concentration) of the primer used in Example 4 was shown to a second person.1! - It was immersed in a trichloroethane solution, subjected to wave energy treatment in the same manner as in Example 4, and dried in the same manner as in Example 1. 8 The treated surface was coated with urethane urethane Gakuji 1 in the same manner as in Example 4, and the crotch air landing strength was adjusted (h-). The results are shown in Table 2. (Hereinafter, blank space) Table 2 Examples +1-13. Comparative Example 2 The composition (beret) used in Example 4 was carried out @4
Same as (1), a specimen for measuring rP and calibration strength was prepared.This specimen was added to a l, 1.I, It was immersed and subjected to wave energy treatment for the treatment time shown in Table 3 under the same conditions as in Example 4. Then, as in Example IM4, urethane paint was applied and dried. The adhesion strength of the coating was measured.The results are shown in Table 3.Comparative Example 2 was applied without wave energy treatment.
Dip in solution for 0 seconds, dry and apply polyurethane φ material. 3rd table. Moreover, cleaning with conventional solutions, application of primer,
The drying and paint application processes can be simplified, and productivity can be greatly improved. According to the method of the present invention, the treated molded product can be used in a wide variety of ways to achieve the above effects. Typical applications of the processed molded product include exterior parts such as automobile bumpers and bumper corners, interior parts such as instrument panels, and two-wheeled parts such as fenders.

Claims (1)

[Claims] This is a method in which the surface of a molded article of a composition containing at least two types of propylene polymers is treated with wave energy having a frequency of 15 to 50 KHz in an organic solvent containing a primer for polypropylene. Among these, (A) one is a propylene homopolymer with a xylene soluble content of at most 5.0% by weight at a temperature of 30°C, or a propylene-ethylene random copolymer with an ethylene copolymerization ratio of at most 10% by weight; It is a combination, (
B) The other is an ethylene-propylene random copolymer having a xylene insoluble content of at most 5.0% by weight at a temperature of 30°C and a propylene copolymerization ratio of 35 to 75% by weight, and a propylene homopolymer. The composition ratio of the ethylene-propylene random copolymer in the total amount of the combined, propylene-ethylene random copolymer and ethylene-propylene random copolymer is 5.0 to 40% by weight, and Melt index is 2
．． The primer is a one-component primer that has a functional group capable of bonding with a compound having an isocyanate group and can form a film on the surface of a molded product, and the organic solvent has a melting point of 20 g/10 min. ℃ or less, and the boiling point is 50
℃ or higher, is capable of dissolving the ethylene-propylene random copolymer, and is chemically inert to all polymers and primers. Method.