JPH039938B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a method for surface modification of a polyvinyl chloride resin molded article, and more specifically, on the surface of a polyvinyl chloride resin molded article,
Low-temperature plasma treatment is applied at the same time as fluorination treatment,
This invention relates to a surface modification method that permanently prevents surface migration of coating agents and the like. BACKGROUND ART Flexible polyvinyl chloride resins have good processability, high strength, and are inexpensive, so they are used in a wide range of applications. However, soft polyvinyl chloride resin moldings contain large amounts of plasticizers and fillers, which tend to migrate to the surface of the molding and ooze out over time, resulting in poor antifouling properties. Durability is unsatisfactory. In order to solve the above problems, a method has been adopted in which an acrylic resin film or a polytetrafluoroethylene film that does not contain additives such as plasticizers is attached to the surface of a soft polyvinyl chloride resin molded body. . However, this method also has various drawbacks. For example, when an acrylic resin film is used, if the adhesive force between the polyvinyl chloride resin molding and the acrylic resin film becomes excessive, cracks may occur on the polyvinyl chloride resin molding depending on how the stress is applied. Furthermore, if the adhesive force is too low, the two may easily peel off, making it difficult to control the adhesive force between the two. Furthermore, when polytetrafluoroethylene film is used, it requires the use of an adhesive and a special bonding process, which raises the problem of increased raw material and process costs. Therefore, a method was developed in which a soft polyvinyl chloride resin molded body is treated with low-temperature plasma in an inorganic gas atmosphere. A polyvinyl chloride crosslinked layer is formed on the surface of the molded product obtained by this method, reducing migration and exudation of additives. However, with this method, the durability of the ability to prevent plasticizer migration against ultraviolet light is low.
In fact, a polyvinyl chloride resin sheet treated with low-temperature plasma of inorganic gas is used as a sunshine weather meter (WFL-SUN-TC manufactured by Suga Test Instruments Co., Ltd.).
It was found that when treated with ultraviolet rays, the sheet had the ability to completely prevent plasticizer migration immediately after low-temperature plasma treatment, but after just 20 hours of ultraviolet irradiation, the amount of plasticizer migration returned to the same level as a non-plasma-treated sheet. are doing. JP-A-56-118430 discloses that a crosslinked layer is formed on the surface of a polyvinyl chloride resin molded article by radiation irradiation, ultraviolet irradiation, or low-temperature plasma treatment,
A method of fluorinating a part of this crosslinked layer with fluorine gas, and a method of subjecting the surface of the polyvinyl chloride resin molded article to low temperature plasma treatment in an atmosphere containing fluorine or Freon gas, and A method of forming a fluorinated crosslinked layer is disclosed. However, even with these methods, the sustainability of the plasticizer migration prevention effect against ultraviolet rays is unsatisfactory, and the degree of fluorine residual on the surface of the molded product (measured with Shimadzu ESCA-750) is also low, making it even more difficult to Improvements were desired. Therefore, the present inventors have proposed, as an improved method, the use of a mixed gas containing at least one type of fluorocarbon and hydrogen as the fluorination treatment gas. In addition, the present inventors have proposed another improvement method in which a modifier consisting of at least one organic compound having an acryloyl group and/or methacryloyl group as a terminal group is mixed into a polyvinyl chloride resin. They also proposed treating the surface of molded products made from physical objects with low-temperature plasma. Although these methods were excellent in practical use, there was a desire in the industry to develop an improved method that could more permanently prevent plasticizer migration caused by ultraviolet rays. Problems to be Solved by the Invention (a) At least a portion of the surface of a polyvinyl chloride resin molded product must be permanently fluorinated. (b) Permanently prevent surface migration and exudation of additives such as plasticizers. (c) Solve the above problems (a) and (b) by using a simple method and a small amount of modifier, and at the same time impair the chemical or physical properties of polyvinyl chloride resin molded products. That there is no. Means and Effects for Solving the Problems The method for surface modification of polyvinyl chloride resin molded articles of the present invention comprises 100 parts by weight of polyvinyl chloride resin and 0.2 to 30 parts by weight of acryloyl group and methane. A method of subjecting the surface of a molded article made from a composition comprising: a modifier consisting of at least one organic compound having at least one terminal group selected from acryloyl groups to a low-temperature plasma treatment. , the plasma treatment is performed using a mixture of at least one type of fluorocarbon and hydrogen gas, and the following relational expression: 0.2A≦B<2.0A [However, in the above formula, A is the content (volume) of the fluorocarbon. and B represents the hydrogen content (volume)]. By the above method of the present invention, a crosslinked layer that is at least partially fluorinated is formed on the surface of a polyvinyl chloride resin molded product, which has extremely high performance in preventing additives such as plasticizers from migrating to the surface and exuding out. A modified surface with extremely high durability against ultraviolet rays can be obtained. The polyvinyl chloride resins used in the method of the present invention include soft polyvinyl chloride resins, hard polyvinyl chloride resins, copolymer resins of vinyl chloride and olefins such as ethylene, propylene, or isobutylene, and vinyl chloride resins. and styrene, copolymer resins of vinyl chloride and dienes such as butadiene or isoprene, copolymer resins of vinyl chloride and acrylic acid, halogenated olefins, or vinyl acetate. , and the above resin and a modifying resin, for example,
There are resins mixed with rubber such as ABS, SBR, or NBR. The polyvinyl chloride resin may contain plasticizers, stabilizers, fillers, flame retardants, flame retardants, antioxidants, ultraviolet absorbers, antifouling agents, lubricants, pigments, etc., as appropriate depending on the purpose. . In the method of the present invention, 0.2 to 30 parts by weight of a modifier is mixed with 100 parts by weight of a polyvinyl chloride resin. When the amount of the modifier is less than 0.2 parts by weight, the surface modification effect obtained is insufficient, and when it is more than 30 parts by weight, the chemical or physical properties of the resulting molded product are unsatisfactory. becomes. The modifier used in the method of the present invention has at least one terminal group selected from acryloyl group ( _CH2 =CH-CO-) and methacryloyl group ( _CH2 =C( _CH3 )-CO-). It is composed of at least one kind of organic compound having the following properties, and the desired surface modification effect can be obtained by using a small amount. _The organic compound used in the modifier of the present invention has, for example, the following general formulas () to (): A(-M) _-o1R () _A1 ( _-M1 ) _-o2A2 ) _A3 (- M ₂ −N) − _o3 A ₄ () [However, in the above formulas () to (), A, A ₁ , A ₂ ,
A ₃ , A ₄ , A ₅ , A ₆ , A ₇ , A ₈ , A ₉ , A ₁₀ and A ₁₁
each independently represents an acryloyl group,
Alternatively, it represents a methacryloyl group, and M, M ₁ and M ₂ each independently represent an aliphatic 2
Represents the alcohol residue, M ₃ , M ₄ and M ₅
each independently represents an aliphatic trihydric alcohol residue; R is an alkyl group, an alkyl group substituted with at least one hydroxyl group, an alkyl group substituted with at least one carboxyl group; alkyl group,
selected from phenyl groups, alkylphenyl groups, phenyl groups and alkylphenyl groups substituted with at least one hydroxyl group, and phenyl groups and alkylphenyl groups substituted with at least one carboxyl group N represents a dibasic acid residue, n ₁ represents an integer of 0 or 1 or more, and n ₂ , n ₃ , n ₄ and n ₅ each independently represent a group of 1 or more. [representing an integer of ] can be selected from the compounds. Examples of the compound represented by the above general formula () include phenyl polyethylene glycol acrylate or methacrylate, p-(noniphenyl)-polyethylene glycol acrylate or methacrylate, 2-hydroxy-3-phenoxypropyl acrylate or methacrylate, monophthalate ester ethylene Examples include glycol acrylate or methacrylate, and 2-ethylhexyl acrylate or methacrylate. Compounds represented by general formulas () and () include polyethylene glycol diacrylate or dimethacrylate, polyethylene glycol monoacrylate monomethacrylate, tripropylene glycol diacrylate or dimethacrylate, tripropylene glycol monoacrylate monomethacrylate, 1,4 -butylene glycol diacrylate or dimethacrylate, 1,4-butylene glycol monoacrylate monomethacrylate, phthalic acid ethylene glycol oligoester diacrylate or dimethacrylate, and phthalic acid ethylene glycol oligoester monoacrylate monomethacrylate. Compounds of general formula () include pentaerythritol triacrylate or trimethacrylate. Examples of the polyfunctional oligoester compound of general formula () include phthalic acid pentaerythritol oligoester triacrylate or trimethacrylate. In the compound of the above general formula ()-(), aliphatic dihydric alcohol residues are represented by M, M ₁ and M ₂ and aliphatic 3 residues are represented by M ₃ , M ₄ and M ₅ At least one type of molecular chain of the alcohol residue and the dibasic acid residue represented by N may contain at least one type selected from an isocyanate group and an epoxy group. . A crosslinking agent may be used together with the modifier used in the present invention to promote its surface modification effect.
Examples of such crosslinking agents include hydroperoxides such as t-butyl hydroperoxide and cumene hydroperoxide, dialkyl peroxides such as di-t-butyl peroxide and di-t-amyl peroxide, lauroyl peroxide, Diacyl peroxides such as stearoyl peroxide are effective, but the sensitizer is not limited thereto, and other known sensitizers can be selected and used. The amount of the crosslinking agent to be used can be selected as appropriate and used, but it is usually preferably within the range of 0.1 to 3% by weight based on the weight of the modifier used. The polyvinyl chloride resin and the modifier are kneaded by a conventional method, and the resulting composition is used to form a desired molded article. This molding method is not particularly limited and can be conventional extrusion molding, dipping method, coating method,
Casting methods, injection molding, calendar molding, inflation molding, compression molding, etc. can be used. The obtained molded article is subjected to low temperature plasma surface treatment in a fluorination treatment gas atmosphere. The low-temperature plasma treatment of the method of the present invention is carried out in a fluorination treatment gas atmosphere, and this fluorination treatment gas contains at least one kind of fluorocarbon and hydrogen, and if necessary at least one kind of inorganic Preferably, a gas is included. Fluorocarbon is perfluorocarbon,
Perfluorocarbons such as tetrafluoromethane, hexafluoroethane, perfluoropropane, perfluoro-n-butane, perfluoropentane, and -n-hexane and the like are preferred. Particularly preferred fluorocarbons for the method of the invention are perfluorocarbons represented by the general formula C _o F _2o+2 , where n represents 1, 2 or 3. In the composition of the fluorinated gas, the fluorocarbon content in the fluorinated gas is determined by considering the effect of preventing surface migration and exudation of additives such as plasticizers, and the water repellency of the resulting modified surface of the molded product. The hydrogen content is expressed by the following formula (a): 0.2A≦B≦2.0A (a) [However, in the above formula, A represents the fluorocarbon content (volume), and B represents the hydrogen content. (represents volume)] It is necessary to satisfy the following. When 0.2A>B, the effect of preventing additive migration and oozing on the modified surface of the molded article becomes unsatisfactory. Furthermore, the present inventors have discovered that when the hydrogen content B is greater than 2.0A, the water repellency of the modified surface of the molded article tends to decrease and the hydrophilicity tends to become excessive. This phenomenon was determined by the inventor of the present invention by measuring the water contact angle on the surface of the molded body using a contact angle meter (Model CA-D manufactured by Kyowa Kagaku Co., Ltd.).
This was confirmed by measuring the amount of fluorine introduced into the surface using ESA (ESCA-750 manufactured by Shimadzu Corporation). The fluorination treatment gas used in the method of the present invention is
As mentioned above, the fluorocarbon content A and
By adjusting the hydrogen content B, it is possible to control the hydrophilicity and water repellency so that the water contact angle of the modified surface is in the range of about 125 to 70 degrees. In particular, the resulting modified surface
In order to have suitable antifouling properties, abrasion resistance, water and oil repellency, and to completely prevent surface migration and oozing of additives such as plasticizers, the above relationship (a) must be satisfied. It is necessary to adjust the fluorocarbon and hydrogen content accordingly. Inorganic gases that can be added to the fluorination treatment gas are preferably CO, Ar, He, _CO2 , and
It is selected from _N2 , etc., and is particularly preferably selected from CO and Ar. There is no particular limitation on the content of inorganic gas. However, the present inventors have found that by setting the content of inorganic gas to an appropriate value in relation to the content of hydrogen gas, the hydrogen content necessary to achieve the desired effect, the power required for processing, and It has been found that processing time can be saved. In other words, the content of inorganic gas and hydrogen in the fluorination treatment gas is determined by the following formula (b): C≧50/B (b) [However, in the above formula, B is the hydrogen content ( C is the content (volume) of inorganic gas
By setting so as to satisfy the following, it is possible to reduce the amount of hydrogen used and the processing power, shorten the processing time, and improve the safety and economic efficiency of the processing process. There is no particular limitation on the method of generating low-temperature plasma in the method of the present invention, and conventionally known glow discharge methods,
Either a corona discharge method or a microwave discharge method may be used. Further, there is no particular limitation on the electrode type in the low-temperature plasma generator, and it may be any of the conventionally used electrodeless type, parallel plate electrode type, internal electrode type, and external electrode type. In low-temperature plasma processing, the pressure inside the processing equipment is 0.01
Performed at low pressure of ~10Torr. Although the processing power is not particularly limited, if it is extremely low, it will be difficult to discharge and form plasma, and if it is extremely high, the etching effect of fluorine on the surface of the molded product will be excessive, and the addition of plasticizers etc. The effect of preventing substances from migrating to the surface or seeping out tends to be insufficient. Further, although the treatment time is not particularly limited, if it is too long, the surface of the molded product tends to yellow. Furthermore, if the length is too short, the processing effect will be insufficient. The method of the present invention will be further explained below by way of examples. Example 1 and Comparative Example 1 Polyvinyl chloride resin with the following composition: Polyvinyl chloride (Kanevinyl S1003)
100 parts by weight DOP 60 〃 Epoxidized soybean oil 3 〃 Ba-Zn stabilizer 2 〃 were heated at 160°C and kneaded for a time using heated rolls.
The mixture was heated and kneaded for 10 minutes and formed into a film with a thickness of 0.3 mm. This was designated as Sample 1 (Comparative Example 1).
Next, 15 parts of phenyl polyethylene glycol acrylate as an acryloyl group-containing organic compound was added to the mixture having the above composition, and the mixture was formed into a film under the same conditions as above, and this was designated as Sample 2 (Example 1). The test pieces taken from these polyvinyl chloride resin films were placed in a predetermined position in a low-temperature plasma processing device, and the pressure inside the device was evacuated to 10 ^-5 Torr.
A mixed gas of hexafluoroethane gas and hydrogen at a volume ratio of 2:1 is introduced into this, and the pressure inside the device is reduced.
The temperature was adjusted to 3 Torr, and low-temperature plasma treatment was performed under the following conditions. High frequency power supply: 13.56 MHz (manufactured by Nippon Koshuha Co., Ltd.) Power consumption: 50 watts Processing time: 10 minutes The water contact angle of the obtained treated specimen was measured using a contact angle meter model CA-D, manufactured by Kyowa Kagaku Co., Ltd. Furthermore, the amount of plasticizer extracted from the surface was measured using the method below. That is, a test piece was placed at the bottom of a Bergier type extraction tester, and 50 ml of hexane was added to it. The contact area between hexane and the test piece was 23.7 cm ² . The test device was shaken for 5 hours at a temperature of 40°C. Next, the amount of DOP (dioctyl phthalate) extracted into hexane was measured by gas chromatography using dinonyl phthalate as an internal standard. The accelerated weather resistance test was conducted using the WEL-SUN-TC model (Suga Test Machine).
(manufactured by Co., Ltd.). Also, the stain test
This was done in accordance with JISL1021. Here, the rotation speed is
The suction power for 100 times is 1.1cm ³ /min, and the degree of contamination is
Measured using JISL0805 gray scale for contamination. The results are shown in Table 1. As is clear from Table 1, the addition of an acryloyl group-containing compound improves the sustainability or durability of the surface-fluorinated crosslinked layer in the accelerated weather resistance test.

[Table] Example 2 and Comparative Example 2 In Example 2, the same operations as in Example 1 were performed. However, as an acryloyl group-containing organic compound,
5 parts of 1,4-butylene glycol diacrylate was used. In addition, the introduction pressure of hexafluoroethane is 0.15 Torr, and the amount of hydrogen mixed with it is:
As shown in FIG. 1, the amount (volume) of hexafluoroethane was varied between 1 and 300%. In addition, the power consumption during low-temperature plasma processing was set at 100 watts. In Comparative Example 2, the same film as in Comparative Example 1 was subjected to the same treatment as in Example 2 without using the modifying material. Figure 1 shows the relationship between the hydrogen/hexafluoroethane volume ratio, the amount of plasticizer extracted from the modified molded product, and the water contact angle on the modified surface in the surface-treated films of Example 2 and Comparative Example 2. . Moreover, among the samples of Example 2 and Comparative Example 2 shown in FIG.
Hydrogen/hexafluoroethane volume ratio is 1:1
The same test as in Example 1 was conducted on the (100%) sample. The results are shown in Table 2.

[Table] As is clear from Figure 1 and Table 2, by adding hydrogen to hexafluoroethane,
Even if the amount of hexafluoroethane introduced is small, an excellent surface modification effect can be achieved. In addition, Figure 1 shows that in order to obtain a modified surface that exhibits a relatively high water contact angle, that is, hydrophilicity, and a small amount of plasticizer extraction, the hydrogen content should be adjusted to 20 to 200% of the hexafluoroethane content. This indicates that it is preferable to keep the value within the range of . Examples 3 and 4 In each of Examples 3 and 4, the same operations as in Example 1 were performed. However, as a modifier, 2 parts of phthalate ethylene glycol oligoester diacrylate (Example 3) and 0.5 part (Example 4)
Using. For the unsurface-treated films prepared in each example, the composition of the fluorinated gas was varied in the range of 20 sccm of hexafluoroethane, 4, 6, and 8 sccm of hydrogen gas, and 0 to 20 sccm of argon gas. Surface treatment was performed under similar conditions. Also. In the low-temperature plasma treatment, the power consumption was 50 W and the treatment time was 5 minutes. The amount of plasticizer extracted from the obtained modified molded body is shown in FIG. FIG. 2 shows that the reduction in plasticizer extraction can be enhanced by adding argon gas to the fluorination treatment gas. In particular, in this example, although the power consumption and treatment time in low-temperature plasma treatment were each half of those in Example 2, plasticizer extraction was achieved by adjusting the amount of argon gas added. This shows that the amount can be reduced to zero. In other words, when the amount of hydrogen gas fed is 8 sccm and B/A = 0.4, if the amount of argon gas fed is 8 sccm or more, the relationship (C≧8)>(50/8=6.25) is established.
The amount of plasticizer extracted is zero. Also, when the amount of hydrogen gas fed is 6sccm and B/A=0.3, if the amount of argon gas fed is 10sccm or more, the relationship (C≧10)>(50/6=8.33) is established. However, the amount of plasticizer extracted is zero. Furthermore, when the amount of hydrogen gas fed is 4 sccm and B/A = 0.2, if the amount of argon gas fed is 14 sccm or more, the relationship (C≧14)>(50/4=12.5) holds, The amount of plasticizer extracted is zero. As is clear from the above facts, even if the amount of hydrogen gas used is decreased by increasing the amount of argon gas, it is possible to reduce the amount of plasticizer extracted to zero. Furthermore, among the samples of Examples 3 and 4 that were surface-treated in this way, the flow rates of hexafluoroethane/hydrogen/argon were 20 sccm/6 sccm/10 sccm.
The same tests as in Examples 1 and 2 were repeated on the samples obtained. The results are shown in Table 3.

[Table] As is clear from FIG. 2 and Table 3, when an acryloyl group-containing compound is added, the desired effect can be sufficiently achieved even if the amount added is small. Effects of the Invention A fluorinated crosslinked layer containing a modifier is formed on the surface of the surface-modified polyvinyl chloride resin molded product obtained by the method of the present invention. The crosslinked surface layer sufficiently prevents surface migration, exudation, and volatilization of additives such as plasticizers, thereby effectively preventing hardening and deterioration of the molded article. In particular, the fluorinated crosslinked surface layer has excellent durability even under ultraviolet irradiation, and therefore exhibits excellent stain resistance over a long period of time even outdoors. Due to the effects of the present invention described above, polyvinyl chloride resin molded products surface-modified by the method of the present invention,
It is extremely useful for outdoor tents, sunshade sheets, car seats, flexible containers, etc., and can also be widely used indoors for wallpaper, blinds, tablecloths, etc.

[Brief explanation of the drawing]

FIG. 1 shows the method of the present invention and the comparative method.
FIG. 2 is a graph showing the relationship between the hydrogen/hexafluoroethane volume ratio of the fluorination treatment gas, the amount of plasticizer extracted from the obtained molded article, and the water contact angle. It is a graph showing the relationship between the hydrogen gas content in the processing gas, the amount of argon introduced, and the amount of plasticizer extracted from the obtained molded product.

Claims (1)

[Scope of Claims] 1. 100 parts by weight of a polyvinyl chloride resin and 0.2 to 30 parts by weight of at least one organic compound having at least one terminal group selected from acryloyl and methacryloyl groups. A method of applying low temperature plasma treatment to the surface of a molded article made from a composition comprising a modifier comprising: a mixture of at least one fluorocarbon and hydrogen gas; and a fluorinated gas that satisfies the following relational expression: 0.2A≦B<2.0A [However, in the above formula, A represents the fluorocarbon content (volume) and B represents the hydrogen content (volume)]. A method for surface modification of a polyvinyl chloride resin molded product, characterized in that the modification is carried out in an atmosphere of 2 The modifier has the following general formula () to (): A(-M) _-o1 R () _A1 ( _-M1 ) _{-o2 A2} () _A3 ( _-M2- N) _-o3 A ₄ () [However, in the above formula, A, A ₁ , A ₂ , A ₃ , A ₄ , A ₅ ,
A ₆ , A ₇ , A ₈ , A ₉ , A ₁₀ and A ₁₁ each independently represent an acryloyl group or a methacryloyl group, and M, M ₁ and M ₂ each independently represent an aliphatic group. Represents a group dihydric alcohol residue, M ₃ ,
M ₄ and M ₅ are each independently an aliphatic 3
Represents a hydrolic alcohol residue, R is an alkyl group, an alkyl group substituted with at least one hydroxyl group,
Alkyl groups substituted with at least one carboxyl group, phenyl groups, alkylphenyl groups, phenyl groups and alkylphenyl groups substituted with at least one hydroxyl group, and phenyl groups substituted with at least one carboxyl group and alkyl phenyl group, N
represents a dibasic acid residue, n ₁ represents an integer of 0 or 1 or more, and n ₂ , n ₃ , n ₄ and n ₅ each independently represent an integer of 1 or more]. The method according to claim 1, which comprises at least one selected from organic compounds. 3 In the general formulas () to (), M,
aliphatic dihydric alcohol residues represented by M ₁ and M ₂ ; aliphatic trihydric alcohol residues represented by M ₃ , M ₄ and M ₅ ; and dibasic acid residues represented by N. The method according to claim 2, wherein at least one kind of molecular chain contains at least one kind selected from isocyanate groups and epoxy groups. 4. The method according to claim 1, wherein the fluorocarbon is selected from perfluorocarbons of the general formula: C _o F _2o+2 , where n represents 1, 2 or 3. 5. The fluorination treatment gas contains the at least 1
2. The method of claim 1, further comprising at least one inorganic gas in addition to the fluorocarbon species and hydrogen. 6 The content (volume) of inorganic gas and hydrogen in the fluorination treatment gas has the following relationship: C≧50/B [However, in the above formula, B represents the content (volume) of hydrogen, and C represents the content (volume) of inorganic gas. 7 The inorganic gas is CO, Ar, He, CO ₂ and
6. The method of claim 5, wherein the method is selected from N ₂ . 8. The method of claim 1, wherein the low temperature plasma treatment is performed at a low pressure of 0.01 to 10 Torr.