JPH0322898B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing an anti-blocking soft vinyl chloride resin film. More specifically, when producing a soft vinyl chloride resin film continuously, before winding the film into a roll, an anti-blocking agent is sprayed on at least one side of the film to impair the smoothness of the film surface. The present invention also relates to a method for producing an anti-adhesive soft vinyl chloride resin film that does not impair the appearance and transparency of the resulting film even if the film sprayed with an anti-adhesive agent is recycled. be. Soft vinyl chloride resin film, which is made by blending a large amount of plasticizer with vinyl chloride resin, is generally manufactured continuously by a calendar molding method, and the film is wound into a roll and transported in a roll. , stored, traded, and used. Soft vinyl chloride resin films have a wide variety of uses, including everyday goods, clothing, and covering agricultural greenhouses. Then, depending on the intended use, the material is unwound from the roll, cut, and subjected to so-called secondary processing such as welding. Add 30PHR of plasticizer to the base vinyl chloride resin.
The soft vinyl chloride resin film prepared by blending the above ingredients has a sticky surface, and when the film is wound into a roll, the surfaces tend to adhere to each other. Rolled films with surfaces that adhere to each other are difficult to unwind during secondary processing, and workability is extremely poor.
In some cases, the surfaces of products obtained through secondary processing often adhered to each other, resulting in defective products. As a method to eliminate the above problem, a method has been proposed in which a soft vinyl chloride resin film is continuously manufactured and an anti-blocking agent such as starch or talc is sprayed on the surface of the film immediately before it is wound into a roll. , has been put into practical use. However, these fine powder anti-blocking agents such as starch and talc are not compatible with soft vinyl chloride resins, so if the scraps generated from the films sprayed with these anti-blocking agents are recycled, the film will be damaged. Problems such as leakage and loss of transparency may occur. For this reason, the above method is suitable for colored products,
It can only be used for products where transparency is not important, such as opaque products. In addition, the soft vinyl chloride resin film used to cover agricultural greenhouses needs to transmit as much sunlight as possible into the greenhouse. Therefore, the anti-adhesive fine powder sprinkled on the film surface during film production is removed from the film surface together with rainwater or water droplets generated inside the greenhouse within a short period of time after being used to coat agricultural greenhouses. It must be. From this point of view, soft vinyl chloride resin films used for covering agricultural greenhouses are not sprayed with anti-blocking agents such as starch or talc during film manufacturing, but are sprayed or used during secondary processing. It was often done. In order to eliminate the above problems when performing secondary processing,
When a film is unwound from a roll, a method is used in which fine powder such as starch or talc is sprinkled on the surface of the unwound film. However, when spraying anti-adhesive powders such as starch and talc on the surface of the film, not only do the fine powders scatter into the air, making the working environment extremely bad, but there is also a large loss of fine powders. There is a problem. In order to prevent the scattering of fine powder into the air, some secondary processing plants have adopted the method of using a dedicated fine powder spreader, but in most secondary processing plants, such a method is not used. It is not adopted and processing work is carried out under adverse conditions. Under these circumstances, there has been a need for a flexible vinyl chloride resin film that is non-tacky and has good workability during secondary processing. Under such circumstances, the present inventors have found that the surface smoothness of the soft vinyl chloride resin film is not impaired, and even if the film is recycled, the appearance and transparency of the resulting film can be improved. The present invention has been completed as a result of extensive research aimed at providing a method for producing a non-stick soft vinyl chloride resin film that does not cause damage. However, the gist of the present invention is to form a resin composition containing 30 to 100 parts by weight of a plasticizer per 100 parts by weight of a vinyl chloride resin into a film, and before winding it into a roll, at least one side of the film is coated. , a method for producing an anti-adhesive soft vinyl chloride resin film, characterized in that powder of a partially saponified polyvinyl alcohol having a degree of saponification of 40 to 70% and an average particle size of 3 to 20 microns is dispersed. . The present invention will be explained in detail below. In the present invention, the vinyl chloride resin refers to polyvinyl chloride and a copolymer mainly composed of vinyl chloride. Monomers copolymerizable with vinyl chloride include vinyl esters, vinyl ethers, acrylic acid or methacrylic acid and their esters, maleic acid or fumaric acid and their esters, maleic anhydride, aromatic vinyl compounds, Examples include halogenated vinylidene compounds, acrylonitrile, methacrylonitrile, ethylene, and propylene. To soften the above vinyl chloride resin, resin
30 to 100 parts by weight of plasticizer is added to 100 parts by weight. Plasticizers that can be used include phthalate esters such as dioctyl phthalate, dibutyl phthalate, butylbenzyl phthalate, dibenzyl phthalate, diisodelphthalate, didodecyl phthalate, and diundecyl phthalate; dioctyl adipate, n-adipate; Aliphatic dibasic acid esters such as butyl and dibutyl sebacate; glycol esters such as pentaerythritol ester and diethylene glycol benzoate; fatty acid esters such as methyl acetyl ricinoleate; phosphoric acids such as tricresyl phosphate and triphenyl phosphate Esters; Epoxidized oils such as epoxidized soybean oil and epoxidized linseed oil; Citric acid esters such as acetyl tributyl citrate, acetyl trioctyl citrate, and tri-n-butyl citrate; Trialkyl trimellitate, tetra -n-octylpyromellitate, polypropylene adipate, and other plasticizers with various structures such as polyesters. In addition to the above-mentioned plasticizer, the vinyl chloride resin may contain various usual resin additives, such as lubricants, as needed.
Antioxidants, ultraviolet absorbers, light stabilizers, dyes, pigments, fillers, flame retardants, etc. can be added. These resin additives can be selected in the usual amount, for example, within the range of 5 parts by weight or less per 100 parts by weight of the base vinyl chloride resin. To blend plasticizers and various resin additives into the base vinyl chloride resin, use conventional mixing and blending techniques such as a ribbon blender, Banbury mixer, super mixer, and other conventionally known blenders and mixers. Bye. In the method of the present invention, the vinyl chloride resin composition containing the plasticizer is formed into a film. To form a film from the vinyl chloride resin composition,
Techniques such as extrusion molding methods such as T-die method and inflation method, calender molding method, and casting method can be employed. The film is preferably wide and long, and its thickness is preferably selected from the range of 0.005 to 1 mm. In the method of the present invention, before the film is wound into a roll, at least one side of the film is coated with a partially saponified polyvinyl alcohol having a saponification degree of 40 to 70% and an average particle size of 3 to 20 microns. Spread the powder. This partially saponified polyvinyl alcohol powder adheres to the surface of a soft vinyl chloride resin film and has the function of preventing the film surfaces from adhering to each other. or dissolved in water droplets,
It exhibits the property of being easily removed from the film surface. According to the present invention, the partially saponified polyvinyl alcohol powder sprinkled on at least one surface of the film has a degree of saponification of 40 to 70%. The reason why the degree of saponification of the partially saponified polyvinyl alcohol is set in this range is that if the degree of saponification is set in the above range, the refractive index of this product should be a value close to that of the soft vinyl chloride resin composition that is the base material. This is because it can be done. This not only makes it less noticeable even if powder of partially saponified polyvinyl alcohol is attached to the film surface, but also allows the film with this powder attached to the surface to be recycled and made into a film, and the powder to be mixed inside the film. However, deterioration of the film's appearance and transparency can be prevented. According to the present invention, the partially saponified polyvinyl alcohol powder sprinkled on at least one surface of the film has an average particle size of 3 to 20 microns. If the average particle diameter is smaller than 3 microns, the particles tend to aggregate with each other, and when actually sprayed on the film surface, many particles will aggregate and reach a diameter of several microns, sometimes resulting in large clumps. This is undesirable because when it is sprayed on the film surface, it impairs the smoothness of the film surface. If the average particle size is greater than 20 microns,
Even if the particles are evenly distributed over the film surface, during the process of rolling the film into a roll and storing it, the winding pressure causes the particles to become embedded in the film surface, leaving the film surface grainy (a state in which small irregularities are formed on the surface). ), resulting in a loss of smoothness and a significant decrease in commercial value, which is undesirable. Polyvinyl alcohol powder having the above average particle size can be prepared by the following method. Particles, pellets, etc. of partially saponified polyvinyl alcohol having a degree of saponification of 40 to 70% are obtained and pulverized using a pulverizer. The crusher that can be used in this case includes a jet mill that uses a gas jet, an impact crusher that crushes by impact force, etc., but is not limited to these examples. To classify particles with an average particle diameter of 3 to 20 microns after pulverization, there are conventional methods such as using a wind classifier or making a slurry in a solvent and passing it through. Depending on the classification method. The particles of the partially saponified polyvinyl alcohol mentioned above are hygroscopic, so if you store a film that has been sprinkled on its surface, the particles may change over time and the ability to prevent the films from sticking to each other may deteriorate. . In order to prevent or suppress this change over time, it is preferable to coat the surface of the partially saponified polyvinyl alcohol particles with another substance. Preferred substances for coating the surface of the partially saponified polyvinyl alcohol particles include silicone oil and fluorine compounds. Specific examples of silicone oils include silicone oils with a skeleton of siloxane bonds and silicon atoms containing methyl groups, phenyl groups, hydroxyl groups, etc., such as dimethylpolysiloxane, diphenylpolysiloxane, methylphenylpolysiloxane, dimethyl- Examples include methylphenylpolysiloxane, dimethyl-diphenylpolysiloxane, methylhydrodienepolysiloxane, but are not limited to these examples. Examples of the fluorine-based compound include oligomers of tetrafluoroethylene resin, and fluorine-based compounds containing a perfluoroalkyl group having a functional group such as acrylate or methacrylate at the end. In order to coat the surface of the partially saponified polyvinyl alcohol particles with the above substance, the silicone oil, fluorine compound, etc. are dispersed or dissolved in a solvent, the partially saponified polyvinyl alcohol particles are added thereto, mixed, and the solvent is removed. Just let it evaporate. According to the present invention, the partially saponified polyvinyl alcohol is sprayed on at least one surface of the film before the film is wound into a roll. The spraying method may be a method using a conventionally known device such as an electrostatic duster that utilizes electrostatic charging of particles or a spray machine that uses a rotating drum. The amount of spraying on the film surface can be selected depending on the type of plasticizer mixed in the film, the amount of plasticizer mixed, the secondary processing method of the film, etc.
It is preferably in the range of 0.01gr/m ² to 1.5gr/m ² . If the spray amount is less than 0.01gr/ ^m2 , there will be little effect on preventing adhesion on the film surface, and 1.5gr/ ^m2
A larger amount is not preferable because the amount of spraying is too large and the fine powder is partially deposited on the film, impairing the smoothness of the film surface. A small amount of an anti-blocking agent such as starch or talc may be mixed into the partially saponified polyvinyl alcohol to be sprayed on the surface of the film. The mixing ratio in this case can be appropriately selected depending on the intended use of the film. After the partially saponified polyvinyl alcohol powder is sprinkled on the surface of the film, the film is wound up using a conventional film winding method such as a center winder or a surf-swinder to form a roll-shaped product. The anti-stick soft vinyl chloride resin film obtained in this way is
It can be widely used for daily necessities, clothing, agricultural house coverings, etc. The present invention is as described above, and has particularly remarkable effects as described below, and its industrial utility value is extremely large. (1) The anti-adhesive soft vinyl chloride resin film obtained by the method of the present invention has significantly improved adhesion on the film surface. Therefore,
Even if this film is wound into a roll and stored for a long period of time, the film surfaces will not stick to each other, and the workability is good when performing secondary processing while unwinding the film wound into a roll. There is no possibility that the surfaces of the next processed products will stick to each other. (2) In the method of the present invention, partially saponified polyvinyl alcohol powder with adjusted degree of saponification and average particle size is used as an anti-blocking agent, so the surface smoothness of the film is not impaired, and this powder can be used as an anti-blocking agent. Even if the adhered film is recycled and used, the appearance and transparency of the film will not deteriorate. (3) It is preferable to treat the surface of the partially saponified polyvinyl alcohol powder with silicone oil or a fluorine-based compound before use, since the partially saponified polyvinyl alcohol powder will not change much over time. (4) Since the partially saponified polyvinyl alcohol used in the method of the present invention has the property of being soluble in water, it can be easily removed from the film surface after secondary processing. Therefore, when the film obtained by the method of the present invention is used as a covering material for agricultural greenhouses, etc., the powder adhering to the film surface will dissolve in rainwater and water droplets and be washed away, preventing sunlight from entering the greenhouse. A lot of it will pass through. Hereinafter, the present invention will be explained in detail based on Examples and Comparative Examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. Examples 1 to 5, Comparative Examples 1 to 9 Polyvinyl chloride (=1400) 100 parts by weight of dioctyl phthalate Barium-zinc composite stabilizer as shown in Table 1 2 parts by weight of epoxidized soybean oil 3 Raw materials consisting of; The resin additives were weighed. After mixing these with a super mixer for 10 minutes,
The mixture was kneaded on a roll heated to 165° C., and a transparent soft polyvinyl chloride film having a width of 1000 mm and a thickness of 0.05 mm was produced using an L-shaped calender. The film after it comes out of the calendar roll,
Bring the film temperature to 40°C by contacting it with a cooling roll.
Cooled below ℃. Various anti-blocking agents shown in Table 1 were sprayed onto one side of the film using a drum-type fine powder spray machine (Nitsuka Spray Equipment) at a spraying rate of 0.7 gr/m ² . This film was slit at both ends by 50mm, recycled and made into a film.Finally, the 900mm wide film was wound into a roll to a length of 1000m. The 14 types of film wound into a roll were left in an atmosphere with a temperature of 40°C and a relative humidity of 90% for two weeks, and then the adhesiveness and surface of the film were evaluated using the following method. Smoothness, transparency, and transparency after washing with water were evaluated. The results are shown in Table 1. "Adhesive"...Cut a 100cm square film from a roll, fold it into four pieces and stack them together.
A load of 30 kg was applied on top of this, and it was left in an atmosphere maintained at 40°C for 24 hours. When the load was applied and the film was unraveled, the state of adhesion between the film surfaces was observed. The evaluation results shown in the first vote have the following meanings. ○: Almost no tackiness △: Slight tackiness ×: Significant tackiness "Surface smoothness": The surface of the film evaluated for tackiness above was observed with the naked eye. The evaluation results shown in Table 1 have the following meanings. ○...Surface is extremely smooth. Δ... Some unevenness is observed on the surface ×... Considerable unevenness is observed on the surface. XX... Traces of powder clumping and falling are observed on the surface. "Transparency": A film cut from a roll was held up to a light source, and its transparency was determined visually. The evaluation results shown in Table 1 have the following meanings. ○...Good transparency△...Slightly poor transparency ×...Poor transparency "Transparency after washing"...After cutting a 50cm square film from a roll and immersing it in water at room temperature for 10 minutes , dry the film, and make it "transparent" on
It was evaluated in the same way as the evaluation method. The display of the evaluation results was also the same as above.

【table】

[Table] From Table 1, the following becomes clear. (1) The film obtained by the method of the present invention has significantly improved adhesiveness and has excellent film surface smoothness and transparency. (2) Even if recycled film is mixed with virgin materials, the appearance and transparency of the film will not be adversely affected. (3) When the surface of a partially saponified polyvinyl alcohol product is coated with silicone oil before use, the partially saponified polyvinyl alcohol product undergoes little change over time and has a significant adhesive improvement effect. (4) When polyvinyl alcohol with a degree of saponification exceeding 70% is used, the transparency of the film is slightly reduced (see Comparative Examples 6 and 7). (5) When conventionally known anti-blocking agents such as starch, talc, and magnesium carbonate are used, the smoothness of the film surface and the transparency of the film decrease.

Claims (1)

[Claims] 1. Plasticizer per 100 parts by weight of vinyl chloride resin
A resin composition containing 30 to 100 parts by weight is made into a film,
Before winding up into a roll, at least one side of the film is coated with partially saponified polyvinyl alcohol with a degree of saponification of 40 to 70% and an average particle size of 3.
A method for producing an anti-adhesive soft vinyl chloride resin film, which comprises spraying powder of ~20 microns. 2 The partially saponified polyvinyl alcohol powder is
2. The method for producing an anti-stick soft vinyl chloride resin film according to claim 1, wherein the film is surface-treated with silicone oil, a fluorine compound, or the like.