JPH0560423B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a film having excellent flame retardancy. (Prior Art) (Problems to be Solved by the Invention) Conventionally, methods for making thermoplastic resin films flame retardant include (1) incorporating a flame retardant during polymerization, and (2) melt extrusion of the film. Two methods are known: (1) a method in which a flame retardant is added during the process and then melt-extruded; and (3) a method in which the surface of the film is coated with a flame retardant composition. However, in the thermoplastic resin films obtained in (1) and (2), the flame retardant is thermally decomposed during the melt extrusion process, so deterioration in the physical properties of the film is unavoidable. On the other hand, method (3) is considered to be an excellent method in that it can avoid deterioration of physical properties due to thermal decomposition. A known example of this type of film is polyester film. That is, JP-A-51-24676 discloses that the first component is a thermosetting epoxy resin, and the second component is a thermosetting epoxy resin.
A mixed composition mainly consisting of a liquid phosphoric acid compound or halogen compound as a component and a powder filler that is insoluble in general organic solvents as a third component is dispersed in an organic solvent and applied to a polyester film to make it flame retardant. The method of obtaining polyester film is
Furthermore, in JP-A No. 52-150474, flame retardant such as tetrabromobisphenol A is coated with thermosetting acrylic resin as a binder on the surface of a polyester film having an average center surface roughness of 0.3 to 0.8 μm. A method is disclosed in which a flame-retardant polyester film is obtained by further coating the film with a resin such as a vinyl chloride/vinyl acetate copolymer. However, since all of these methods involve coating the flame retardant and thermosetting resin binder separately on the polyester film, the flame retardant precipitates on the polyester film obtained by these methods, resulting in white powder. There was a problem that this caused an undesirable appearance. Also, to avoid such problems, reducing the amount of flame retardant
There was a problem that the flame retardant effect was insufficient. The present invention aims to solve the problems of conventional flame retardant films as described above. That is, an object of the present invention is to provide a flame-retardant film that does not seep out of flame retardant and has an excellent surface appearance. Another object of the present invention is to provide a flame-retardant film whose physical properties are less likely to deteriorate due to thermal decomposition. (Means for Solving the Problems) In order to solve these problems, the present inventors have made extensive studies and have developed the present invention by laminating a cured phenolaldehyde resin onto a thermoplastic resin film having an affinity for phenol resin. The present invention was achieved by discovering that the above objects can be achieved. That is,
The present invention relates to a flame-retardant film characterized by laminating an effective phenolic aldehyde resin onto a thermoplastic resin film having affinity for phenol resin. Next, the present invention will be explained in detail. The phenol resin-compatible thermoplastic resin film in the present invention refers to a thermoplastic resin film that has an affinity for phenol resin (cured phenol aldehyde resin is simply referred to as phenol resin), and particularly This film is made of thermoplastic resin with excellent adhesion to phenolic resin. "Excellent adhesive" here
This means that the adhesive property can be improved in advance by applying a conventionally known physical or chemical adhesion-improving treatment to the surface, or by providing a surface modification layer (anchor coat) that has strong adhesion to the coating resin. This means that the adhesive has sufficient adhesion to the coating resin to withstand practical use without any treatment to improve it. Specific examples of such a thermoplastic resin film having an affinity for phenol resin include thermoplastic polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyacrylate, and polycarbonate, nylon 6,
Examples include films made of polyamide such as nylon 66 or thermoplastic resin such as polyvinyl alcohol. Further, it may be a film made of a composition of these thermoplastic resins. Among these,
Polyester film is one of the phenol resin-compatible thermoplastic resin films most suitable for the flame-retardant film of the present invention. Such a polyester film is a polyester film obtained by a polycondensation reaction of a dicarboxylic acid component and a glycol component, but it may also be a film of a composition of these polyesters. Examples of the dicarboxylic acid component constituting the polyester include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and naphthalene dicarboxylic acid, as well as aliphatic dicarboxylic acids such as adipic acid and sebacic acid, but mixtures thereof may also be used. good. Examples of the glycol component include aliphatic alkylene glycols such as ethylene glycol and tetramethylene glycol, glycols such as diglycidyl ether of bisphenol A and polyalkylene ether, as well as aromatic diols such as bisphenol A and hydroquinone. , or a mixture thereof. In addition to dicarboxylic acid components and glycol components, paraoxybenzoic acid, lactones, carbonic acid derivatives, and the like may also be used. Examples of films made of polyester compositions include films made of compositions in which two or more of polyethylene terephthalate, polybutylene terephthalate, polyarylate, polycarbonate, polyester carbonate, etc. are combined. The thermoplastic resin used in the phenol resin-compatible thermoplastic resin film of the present invention may contain stabilizers, additives, extenders, dyes and pigments, crosslinking agents, etc., as necessary. Further, by providing a crosslinkable functional group, it can be crosslinked by light, heat, radiation, or the like. Examples of the phenol resin-compatible thermoplastic resin film in the present invention include films obtained by various manufacturing methods such as melt extrusion, calendering, and casting. Furthermore, the thermoplastic resin film having an affinity for phenol resin in the present invention includes not only an unstretched film but also a film stretched uniaxially or biaxially. Furthermore, characters, figures, patterns, etc. may be drawn on the surface of the phenol resin-compatible thermoplastic resin film. The thickness of the phenol resin-compatible thermoplastic resin film in the present invention is not particularly limited, and may be of any thickness, from an extremely thin film to a sheet-like thickness. The cured phenolaldehyde resin laminated on the surface of the phenol resin-compatible thermoplastic resin film in the present invention includes not only cured non-halogenated phenolaldehyde resins, but also
Also included are cured halogenated phenolic aldehyde resins. Phenols constituting the non-halogenated phenol aldehyde resin or the halogenated phenol aldehyde resin include phenol and phenol derivatives. Examples of this phenol derivative include m-alkylphenol substituted with an alkyl group having 1 to 9 carbon atoms, o-
Alkylphenol, p-alkylphenol,
Specifically, in addition to m-cresol, p-ter-butylphenol, o-propylphenol, resorcinol, bisphenol A, etc., these phenols have hydrogen atoms in the benzene nucleus partially or entirely replaced with halogen atoms. and halogenated phenols. Note that the phenols are not limited to these, and may be any other compound containing a phenolic hydroxyl group, or may be a mixture of two or more of these. Further, the halogenated phenolaldehyde resin may be a halogenated phenolaldehyde resin obtained by allowing a halogenating agent to act on a non-halogenated phenolaldehyde resin. Note that this halogenation may be carried out after applying the non-halogenated phenolic aldehyde resin to the phenolic resin-compatible thermoplastic resin film of the present invention and before curing treatment. Examples of such halogenating agents include bromine, chlorine, sulfuryl chloride, sulfuryl bromide, and the like, with bromine being particularly preferred. The halogen content of the halogenated phenolic aldehyde resin is 1 to 30% by weight, especially 3 to 15% by weight.
Weight percent is preferred. When the halogen content exceeds 30% by weight, the curing speed of the halogenated phenolaldehyde resin becomes slow. On the other hand, if it is less than 1% by weight, the flame retardant effect becomes weak. Examples of the aldehydes constituting the non-halogenated phenolic aldehyde resin or the halogenated phenolic aldehyde resin include compounds having an aldehyde group such as formaldehyde, acetaldehyde, and benzaldehyde. The components constituting the phenolaldehyde resin may include not only phenols and aldehydes but also other components. Examples of such other components include ammonia, hexamethylenetetramine, dimethylamine, diethylenetriamine, and the like, which are used as necessary in the production of phenolaldehyde resins.
Examples include alkylamines such as polyethyleneimine. Further, the phenolaldehyde resin may be blended with a thermosetting polymer such as a melamine resin, or may be blended with a thermoplastic polymer such as nylon. In the flame retardant film of the present invention, the thickness of the cured phenol aldehyde resin laminated on the phenol resin-compatible thermoplastic film may be selected from any desired thickness as long as it imparts flame retardancy, but 0.01
~50 μm, particularly preferably 0.1 to 20 μm. If it is less than 0.01 μm, it will be difficult to form a continuous film, and if it exceeds 50 μm, the flexibility of the flame-retardant phenolic resin-compatible thermoplastic resin film will be impaired or cracks will easily form on the surface. . Various methods can be used to laminate the cured phenolaldehyde resin onto the phenol resin-compatible thermoplastic resin film, but for example,
One preferred method is to apply a phenolaldehyde resin dissolved in an organic solvent together with a curing agent if necessary, and then remove the organic solvent and perform a curing treatment. In this case, the organic solvent must be one that can dissolve not only the phenol aldehyde resin but also the curing agent used as necessary at an appropriate concentration, and that it can be easily desolvated after coating, or the phenol resin. Any material can be used as long as it satisfies conditions such as not dissolving the compatible thermoplastic resin film. Examples of such organic solvents include methyl ethyl ketone, acetone, and methanol. Examples of the curing agent used as necessary include hexamethylenetetramine. The organic solvent solution of the phenolaldehyde resin contains not only a curing agent but also an adhesion promoter, a wetting modifier, a plasticizer, a stabilizer, an antioxidant, a lubricant,
Additives such as defoamers, fillers and facial cleansers can also be dissolved. Known methods such as a doctor knife, bar coater, gravure roll coater, reverse coater, curtain coater, air knife coater, and spinner can be used to apply the organic solvent solution of the phenol aldehyde resin to the surface of the phenol resin-compatible thermoplastic resin film. In addition to the application method using a painting tool, spray methods, dipping methods, etc. may be used. After applying an organic solvent solution of a phenol aldehyde resin to the surface of a phenol resin-compatible thermoplastic resin film, the organic solvent is removed, dried, and then hardened. A halogenation treatment is performed as necessary in the process of applying an organic solvent solution of a phenol aldehyde resin to a phenol resin-compatible thermoplastic resin film and then performing a curing treatment. Drying and curing conditions are selected within an appropriate range as long as the above effects are obtained. For example, preferred drying conditions include heating at 40 to 100°C for 1 to 20 minutes, and preferred curing conditions include heating at 100 to 100°C.
At a temperature of 300℃, especially 150-200℃, for 1 second to 20 minutes,
In particular, heating for 5 seconds to 3 minutes is mentioned. The layer of cured phenolaldehyde resin laminated on the phenolic resin-compatible thermoplastic resin film may be a single layer or a multilayer. The cured phenolaldehyde resin may be laminated on either one side or both sides of the phenol resin-compatible thermoplastic resin film. When laminated on one side, a layer of a polymer lower than a cured phenolaldehyde resin or a metal film may be laminated on the other side. Since the thermoplastic resin film having an affinity for phenolic resin of the present invention has an affinity for phenolic resin, when laminating the cured phenolic aldehyde resin of the present invention, it is necessary to apply a physical There is no need to perform any pretreatment to improve the adhesion layer, such as chemical adhesion improvement treatment or surface modification layer anchor coating treatment. Application fields of the flame retardant film of the present invention include:
Examples include the electrical and electronic field, such as flexible printed circuit boards (FPC) used in membrane switches, automobiles, and OA equipment, and electric wire and cable wrapping, and the building materials field, such as agricultural greenhouses. <Examples> Hereinafter, the present invention will be specifically explained using examples. Example 1 200g of phenol was added to the three-necked flask from 1.
200g of 37wt% formalin, 120g of water, 18g of hexamethylenetetramine, and 8.4g of calcium chloride were added with stirring to form a homogeneous solution. To this solution, 40g of a 10wt% solution of sodium fluoride was added under stirring, and the solution was heated for 60 minutes. The temperature was raised to 85° C., and the mixture was reacted at the same temperature for 90 minutes to obtain a suspension of microspherical resol resin. Next, the flask contents were allowed to cool to 30°C,
After adding 0.5 ml of water, the supernatant liquid was removed, and the microspheroidal resin particles in the lower layer were washed with water and air-dried. Next, this was heated for 50 minutes under reduced pressure (5 mmHg or less).
After drying at ~60°C, microspherical resin particles with an average particle size of about 50 μm were obtained. (Resin A) 8 g of Resin A was dissolved in 32 g of methyl ethyl ketone, coated on one side of a 75 μm thick polyethylene terephthalate film using a gravure coater, and dried at 70°C for 1 minute.
Cure for 2 minutes to obtain a polyethylene terephthalate film having a cured coating film with a thickness of 10 μm. (Film A) Example 2 The methyl ethyl ketone solution of Resin A used in Example 1 was coated on both sides of the 75 μm thick polyethylene terephthalate film used in Example 1, and the post-treatment was carried out in the same manner as in Example 1. 5μ each on both sides of polyethylene terephthalate film
A polyethylene terephthalate film with a cured coating film of m thickness was obtained. (Film B) Example 3 Liquid resol resin (PL-3812 manufactured by Gunei Chemical Co., Ltd.)
10g was dissolved in 20g of methyl ethyl ketone, coated on one side of the 75μm thick polyethylene terephthalate film used in Example 1, and then heated at 70°C.
It was dried for 1 minute to form a coating film with a thickness of 10 μm. Then, curing was performed at 170° C. for 2 minutes to obtain a polyethylene terephthalate film having a cured coating. (Film C) Example 4 Resin A used in Example 1 was mixed with methyl ethyl ketone and isopropyl alcohol in a 1:1 (volume ratio)
A 30wt% solution was prepared by dissolving it in a mixed solvent.
This solution was coated on one side of a biaxially stretched nylon 6 film with a thickness of 38 μm using a reverse coater, and dried and cured in the same manner as in Example 1 to form a cured coating film of 7 μm thick. I got the film. (Film D) The flammability of Examples 1 to 4 above was determined by UL-94.
Evaluation was performed according to the VTM method of (Underwriters' Laboratories Inc.). For comparison, a polyethylene terephthalate film (film E) with a thickness of 75 μm and a
The flammability of a 38 μm biaxially stretched nylon 6 film (Film F) was also evaluated. In addition, when a polyethylene terephthalate film was used, the appearance of the film surface was examined after being left at 200°C for one week. The results are shown in Table 1.

[Table] It can be seen that a remarkable flame retardant effect can be obtained simply by laminating a non-halogen cured phenolaldehyde resin on a film such as polyethylene terephthalate or nylon 6. Also, there is no clouding on the surface of the film. Example 5 Polyethylene terephthalate (Nippon Ester Co., Ltd.)
Manufactured by: phenol/tetrachloroethane mixed solvent (1:1 weight ratio) with a relative viscosity of 1.40 at 20°C at a concentration of 0.5 g/dl) and polyarylate (manufactured by Unitika Co., Ltd.)
U polymer: 25 at a concentration of 1 g/dl in a phenol/tetrachloroethane mixed solvent (6:4 weight ratio)
80 parts by weight to 20 parts by weight were mixed and melted to obtain a film with a thickness of 100 μm. (Film G) Resin A used in Example 1 on one side of this film.
A methyl ethyl ketone solution was applied using a gravure coater and dried under the same conditions as in Example 1.
A laminated film with an uncured layer of 10 μm was obtained.
(Film H) Further, a part of the film H was cured under the same conditions as in Example 1 to obtain a film having a laminated cured layer having a thickness of 10 μm. (Film I) Example 6 Polybutylene terephthalate (logarithmic viscosity 1.0)
and polyarylate (manufactured by Unitika Co., Ltd.: U polymer,
(logarithmic viscosity: 0.6) were mixed and melted in a ratio of 80 parts by weight to 20 parts by weight to obtain a film with a thickness of 100 μm.
(Film J) Resin A used in Example 1 on one side of this film.
A methyl ethyl ketone solution was applied using a gravure coater and dried and cured under the same conditions as in Example 1 to form a 10 μm thick cured layer on the surface of the film J. (Film K) The flammability ranks of Films H, I, and K obtained in Examples 5 and 6 were evaluated using the UL-94 VTM method.
For comparison, the flammability of Films G and J was also evaluated. In addition, the appearance of the film surface after being left at 200°C for one week was examined. The results are shown in Table 2.

[Table] Example 7 200g of phenol was added to the three-necked flask from 1.
Add 200g of 37wt% formalin, 120g of water, 18g of hexamethylenetetramine, and 8.4g of calcium chloride to make a homogeneous solution, and add 40g of a 10wt% aqueous solution of sodium fluoride to this solution while stirring.
was added, the temperature was raised to 85°C over 60 minutes, and the reaction was carried out at the same temperature for 90 minutes to obtain an emulsion of microspherical resol resin. Next, the flask contents were allowed to cool to 30°C,
After adding 0.5% water, 570g of 3.5wt% bromine water was added while stirring, and after the liquid color changed from reddish brown to colorless, the mixture was stirred for 5 minutes, the supernatant liquid was removed, and the microspheroidized resin in the lower layer was removed. The particles were washed with water and air dried. Next, this was heated to 50 to 60°C under reduced pressure (5 mmHg or less).
A thermosetting brominated phenol formaldehyde resin having an average particle size of about 50 μm was obtained. The bromine content of this resin was 4.5 wt%. This resin is called resin B. 8 g of the resin B was dissolved in 32 g of methyl ethyl ketone, coated on one side of a 75 μm thick polyethylene terephthalate film, dried at 70°C for 1 minute, and cured at 170°C for 2 minutes to form a cured brominated phenol formaldehyde film with a thickness of 10 μm. A polyethylene terephthalate film laminated with a polyurethane resin was obtained. This film is called film L. Example 8 Using resin B, the same drying and curing conditions as in Example 7 were adopted, and one side of a 75 μm thick polyethylene terephthalate film was coated with a 7 μm thick cured brominated phenol formaldehyde resin. A laminated polyethylene terephthalate film was obtained. This film is called film M. Example 9 Liquid resol resin (PL-3812 manufactured by Gunei Chemical Co., Ltd.)
was dissolved in methyl ethyl ketone to make a solution with a concentration of 30 wt%, and this was coated on one side of a 75 μm thick polyethylene terephthalate film, dried to form a 10 μm thick coating, and then bromine water (3.5 wt%) After being brominated by immersion in a tank, it was cured according to the conditions of Example 5 to obtain a polyethylene terephthalate film. This film is called film N. The bromination rate of this cured resol resin layer is
It was 4.3wt%. The flammability of the films L, M, and N obtained in Examples 7 to 9 was evaluated according to UL-94 (Underwriters' Laboratories).
The evaluation was made according to the VTM method of Inc.). The results are shown in Table 3. In addition, the appearance of the film surface after being left at a temperature of 200° C. for one week was examined.

[Table] From Table 3, the combustion rank of the film laminated with brominated cured phenolaldehyde resin is
It was determined to be VTM-0, and it was revealed that it exhibited excellent flame retardancy. There was also no bleed-out of the flame retardant. (Effects of the Invention) The flame-retardant film of the present invention is made flame-retardant without impairing the characteristics of the phenol resin-compatible thermoplastic resin film. Furthermore, since there is no flame retardant bleed-out, the surface appearance is excellent.
Furthermore, by curing the phenolaldehyde resin, not only does the blocking phenomenon of the flame retardant film of the present invention become less likely to occur, but also the occurrence of scratches on the surface is reduced, and furthermore, the flame retardance after curing is Improved compared to before.

Claims (1)

[Claims] 1. A flame-retardant film characterized by laminating a cured phenolaldehyde resin onto a thermoplastic resin film having an affinity for phenol resin.