JP3362567B2 - Easy embossable film - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a film suitable for embossability. More specifically, the present invention relates to an easily embossable film suitable for producing a decorative board or the like having a decorative property by embossing for use as a building material.

[0002]

2. Description of the Related Art Conventionally, a polyvinyl chloride film has been representatively used as a film used for embossing in building materials, and has been preferably used in terms of flexibility, weather resistance and embossability. . On the other hand, the film has problems such as generation of toxic gas when the film is burned due to fire, bleed-out of plasticizer, etc.
New materials have been demanded due to the recent needs for environmental resistance.

In order to solve these requirements, for example, there is a method of laminating a flexible film and a biaxially stretched polyethylene terephthalate film, and the embossing property is certainly good, but the difference in thermal expansion and contraction between them. Therefore, there is a problem that the film is greatly curled after being subjected to high temperature processing such as embossing.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and not only is it excellent in environmental friendliness, but also curling is less likely to occur even after embossing and good embossing is achieved. An object is to provide an easily embossable film having moldability.

[0005]

The above-mentioned object of the present invention is to provide a layer made of polyester B having a melting point of 220 to 270 ° C. (A layer) on at least one side of a layer made of polyester B having a melting point of 150 to 245 ° C. (B layer). ) Are stacked, DS
Sub peak is lengthened melting point -5 ° C. or less in the range near Ru extension of melting point -5 ° C. or more polyester A polyester B by C
Film having an optical density of 0.2 or more and 1.7 or less
It can be achieved by an easily embossable film characterized by

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The polyester in the present invention is a polymer composed of a dicarboxylic acid component and a glycol component, and examples of the dicarboxylic acid component include terephthalic acid, ishiphthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid and diphenyl. Aromatic dicarboxylic acids such as sulfone dicarboxylic acid, diphenoxyethane dicarboxylic acid, 5-sodium sulfoisophthalic acid, phthalic acid, oxalic acid, succinic acid, adipic acid, sebacic acid, dimer
Acids, maleic acid, fumaric acid and other aliphatic dicarboxylic acids, cyclohexyne dicarboxylic acid and other alicyclic dicarboxylic acids, p
Examples thereof include oxycarboxylic acids such as oxybenzoic acid. Among these dicarboxylic acid components,
Terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid are preferable from the viewpoint of heat resistance. On the other hand, as the glycol component, for example, ethylene glycol, propanediol, butanediol, pentanediol, hexanediol,
Examples thereof include aliphatic glycols such as neopentyl glycol, alicyclic glycols such as cyclohexanedimethanol, and aromatic glycols such as bisphenol A and bisphenol S. Among them, ethylene glycol and butanediol are preferable among these glycol components. Two or more of these dicarboxylic acid components and glycol components may be used in combination.

Further, a polyfunctional compound such as trimellitic acid, trimesic acid and trimethylolpropane may be copolymerized with the copolyester as long as the effects of the present invention are not impaired.

The polyester A used in the present invention has a heat resistance of 220 to 270 ° C. as a melting point,
It is necessary to reduce the difference in thermal expansion and contraction with polyester B. Preferable examples include polyethylene terephthalate and its copolyester, and when the above acid component or glycol component is copolymerized, 0 to 20 mol% of all acid components and / or glycol components constituting the polyester is used. Polymerization is preferable from the viewpoint of heat resistance. If it exceeds 20 mol%, the melting point becomes low, which is disadvantageous in heat resistance and heat stretchability.

The polyester B used in the present invention needs to have a melting point of 150 to 245 ° C. in order to reduce embossability and the difference in thermal expansion and contraction with the polyester B. It is preferable to copolymerize polyethylene terephthalate with isophthalic acid, diethylene glycol, polyalkylene glycol, adipic acid, sebacic acid or the like.

Further, the difference in melting point between polyester A and polyester B is preferably from 5 to 60 ° C. in order to reduce the difference in embossability and heat stretchability, and more preferably from 5 to 50 ° C.

When the polyester component preferably has an intrinsic viscosity of 0.5 to 0.8, more preferably 0.55 to 0.75, the embossed shape is sharp. Therefore, it is preferable.

The easily embossable film in the present invention is required to be biaxially stretched in terms of dimensional stability. The film may be biaxially stretched simultaneously or sequentially, or the film may be uniaxially stretched in the longitudinal direction and then extruded and laminated with another layer and then transversely stretched. In the case of sequential biaxial stretching, it is also possible to perform stretching in the longitudinal direction or the width direction twice or more. The stretching ratio in the longitudinal direction and the width direction of the film can be arbitrarily set according to the degree of orientation, strength, elastic modulus, etc. of the desired film, but is preferably 2.5 to
It is 7.0 times. Either the stretching ratio in the longitudinal direction or the stretching ratio in the width direction may be increased or may be the same. The stretching temperature may be any temperature within the range of the glass transition temperature of the polyester −10 ° C. or higher and the crystallization temperature or lower, but it is usually preferably 80 to 150 ° C. Further, the film can be heat-treated after the biaxial stretching. This heat treatment can be performed by any conventionally known method such as heating in an oven or on a heated roll. In the present invention, it is necessary that the DSC sub-peak derived from the heat treatment temperature is within the range of the melting point of polyester B −5 ° C. or more and the melting point of polyester A −5 ° C. or less in order to prevent embossability and curl of the film. Become. Although the heat treatment time can be set arbitrarily, it is usually preferable to perform the heat treatment for 1 to 60 seconds. The heat treatment may be performed while relaxing the film in its longitudinal direction and / or width direction.

In order to improve the embossability and the film after embossing, the film thickness is 20 to 200 μm.
It is necessary to be. Preferably 30-180μ
m, more preferably 40 to 150 μm.

Further, as the laminated film, the thickness of the polyester B layer is 5 μm or more and 60 μ or more in view of embossability.
It is preferably m or less, and more preferably 10 μm or more and 50 μm or less.

Further, the polyester of the present invention improves the handling property and scratch resistance of the film, and also improves the adhesiveness between the B layer and the printing layer composed of ink or the like and the B layer to prevent blocking. Surface roughness R of layer A
It is preferable that a is 0.01 μm or more and 3 μm or less, and the wetting tension of the B layer is 45 dyne / cm. The surface roughness Ra of the A layer is preferably 0.01 μm or more and 3 μm or less, and more preferably 0.02 μm or more and 1 μm or less. The method of controlling the surface roughness Ra in such a range is not particularly limited, but a method of incorporating particles in the A layer is preferable. Specifically, it is preferable that the inorganic particles and / or the organic particles having an average particle diameter of 0.001 to 8 μm, or the internal particles produced in the polymerization system are contained in an amount of 0.001 to 50% by weight, and further, the average. Particle size 0.1-5μ
Inorganic particles and / or organic particles of m are 0.005 to 3
It is preferably contained in a weight percentage. Examples of the inorganic particles and / or organic particles include wet and dry silica, colloidal silica, titanium oxide, calcium carbonate,
Calcium phosphate, barium sulfate, alumina, mica,
Examples thereof include inorganic particles such as kaolin and clay, and organic particles having styrene, silicone, acrylic acid and the like as a constituent component. Among them, inorganic particles such as wet and dry colloidal silica and alumina, and organic particles having styrene, silicone, acrylic acid, methacrylic acid, polyester, divinylbenzene and the like as constituent components can be mentioned. As the internal particles, those produced by a known method in which an alkali metal compound, an alkaline earth metal compound, etc. are added to the reaction system and a phosphorus compound is further added can be used. Two or more kinds of these inorganic particles and / or organic particles may be used in combination. Furthermore, it is preferable to add the above particles to the B layer as well, but it is not particularly limited.

Further, the wettability of the layer B is more preferably 48 dyne / cm or more, and particularly preferably 50 dyne.
/ Cm or more is preferable. The method for increasing the wetting tension is not particularly limited, but examples of the method include flame treatment, chemical treatment, electric discharge treatment, and coating treatment with polyester for the B layer. Among them, the method of subjecting the surface to corona discharge treatment is preferable because the adhesion to ink is good.
The corona discharge treatment may be carried out in air, nitrogen or carbon dioxide gas, and a mixture thereof, for example, JP-A-1-20.
Processes such as Japanese Patent No. 236 and Japanese Patent Publication No. 57-30854 are preferable. The strength during corona discharge treatment is expressed as an E value. E value = W / (D / V), where W is processing strength (W), D is processing width (m), and V is film speed (m /).
Minutes). The E value is preferably 20 to 60 W / m, more preferably 25 to 55 W / m.

In the film of the present invention, the catalyst and the amount of carboxyl end groups in each layer may be different. When the edge of the film is collected, it may be collected in the polyester A layer or B layer.

The easily embossable film of the present invention preferably has an optical density of 0.2 or more and 1.7 or less from the viewpoint of weather resistance and printability. Examples of the method of setting the optical density as described above include a method of containing titanium oxide, calcium carbonate, zinc white, zinc sulfate, lithopone, lead white, basic lead sulfate, basic lead silicate and the like. Among them, rutile type titanium oxide, anatase type titanium and calcium carbonate are preferable in terms of whiteness.

The easily embossable film of the present invention is preferable because a layer made of an acrylic polymer is further provided on the B layer because the embossability and weather resistance are further improved. The acrylic polymer is preferably polymethylmethacrylic resin, and the thickness of the acrylic polymer layer is 1 μm or more and 50 μm or less, preferably 5 μm.
m to 30 μm.

The above acrylic polymer layer may be adhered to the B layer via an ink, an adhesive layer or the like.

The film of the present invention can be formed into a film by any conventionally known method. Next, the method for producing the film of the present invention will be described, but the invention is not limited thereto.

Polyester A has an average particle size of 0.25
μm Rutile-type titanium oxide 20% -containing isophthalic acid 5 mol% Copolyethylene terephthalate (germanium element amount 42 ppm, IV = 0.54, diethylene glycol 0.89% by weight, melting point 240 ° C.), polyester B
As isophthalic acid 12 mol% copolymerized polyethylene terephthalate (germanium element amount 40 ppm, IV =
0.65, diethylene glycol 1.1% by weight, melting point 2
30 ° C.) are fed to separate twin-screw vent type extruders (extruder temperature is set to melting point + 35 ° C.) and melted, filtered through a 30 μm-cut filter, and then laminated in two layers in a feed block (lamination ratio: 1: 4 (A: B)) and discharged from a normal die, and then electrostatically applied (7 kV) to cool and solidify by a mirror-cooling drum so that the layer B becomes the drum surface to obtain a cast film. The obtained film is vertically oriented at 98 ° C, 2000
The film was stretched 3.4 times at 0% / min, then rapidly cooled to 25 ° C., further stretched 3.7 times at 110 ° C. at 3000% / min, and heat treated at 239 ° C. for 6 seconds and relaxed by 5%. After quenching, a biaxially stretched film is obtained.

Further, in producing the film of the present invention, if necessary, additives such as an antioxidant, a plasticizer, an antistatic agent, a weathering agent and a terminal blocking agent can be appropriately used.

The film obtained as described above is printed and, if necessary, laminated with an acrylic polymer, preheated by a heating roll and shaped by an embossing roll,
It is bonded to a wood board, a synthetic wood board, a metal board, or the like by heat bonding or an adhesive.

[0025]

The present invention will be described in detail below with reference to examples. The characteristics of the polyester film were measured and evaluated by the following methods.

(1) Melting point of polyester and DSC subpeak film were measured by a differential scanning calorimeter (D, manufactured by Perkin Elmer Co., Ltd.).
SC-2 type) at a temperature rising rate of 10 ° C / min. For those whose melting point was difficult to measure, the sample was crystallized and determined.

(2) Intrinsic viscosity of polyester Dissolve polyester in orthochlorophenol and prepare 25
It was measured at ° C.

(3) The resin is removed from the average particle size film by a plasma low temperature ashing method to expose the particles. The treatment conditions are such that the resin is incinerated but the particles are not damaged. The number of particles of 5,000 to 10,000 was observed with a scanning electron microscope, and a particle image was obtained from the equivalent circle diameter by an image processing device.

When the particles are internal particles, a polymer cross section is cut to prepare an ultrathin section having a thickness of about 0.1 to 1 μm, and photographs (10 sheets: 10: (25 cm × 25 cm) was photographed, and the average dispersion diameter of internal particles was calculated from the equivalent circle diameter.

(4) Surface Roughness of Film (Centerline Average Roughness Ra, Maximum Roughness Rt) The layer A surface was measured using a high precision thin film step measuring instrument ET-10 manufactured by Kosaka Laboratory. The conditions are as follows, and the average value of 20 measurements was taken as the value.

-Stylus tip radius: 0.5 μm-Stylus load: 5 mg-Measurement length: 1 mm-Cutoff value: 0.08 mm Note that Ra and Rt are defined, for example, by Jiro Nara, "Surface roughness". Measurement / Evaluation Method "(General Technology Center, 1983)
Are shown in.

(5) Wettability (γ) The wettability was determined according to JIS K-6768. The following three types of standard solutions were used according to the magnitude of surface tension.

30 dyne / cm ≦ γ <56 dyne /
cm: JIS K-6768 standard solution 56 dyne / cm ≦ γ <72 dyne / cm: ammonia water 72 dyne / cm ≦ γ: sodium hydroxide aqueous solution

(6) The optical density films are stacked so as to have a thickness in the vicinity of 150 μm, and the transmission density is measured by an optical densitometer (TR927 manufactured by Macbeth Co.). Plot thickness and optical density, 150μm
The optical density corresponding to the thickness was determined.

(7) A layer and a layer B of the blocking resistant film are laminated (area:
(3 cm x 4 cm) with a load of 300 g / 12 cm ² left at 50 ° C and 80% RH for 24 hours, and then the shear stress of the overlapping portion was measured at a tensile speed of 20 cm / min using a Tensilon tensile tester. The criteria were as follows.

Class A: less than 0.05 kg / 12 cm ² Class B: 0.05 kg / 12 cm ² or more 0.2 kg / 12
Less than cm ² C class: 0.2 kg / 12 cm ² or more

(8) The embossable film is heated to 150 to 230 ° C. to obtain 20 μm and 2
The embossing moldability was evaluated according to the following criteria by passing between an embossing roll having a depth of μm and a pressure cooling roll (2 kg / cm).

Grade A: The depth of the film surface is 70% to 100% of the uneven depth of the embossing roll. Grade B: The depth of the film surface is 50% to less than 70% of the uneven depth of the embossing roll C grade: The depth of the film surface is less than 50% of the uneven depth of the embossing roll

(9) Ink adhesive acrylic emulsion water-based ink (organic pigment 16.5
%, Viscosity extender 5%, acrylic emulsion 40%, plasticizer 2%, isopropyl alcohol 7%, wax 2.
Gravure printing was performed using 5%, morpholine 1%, and water 26%), and after printing, it was left in an atmosphere of 40 ° C. and 90% relative humidity for 24 hours, and then a cellotape peeling test was performed.

The evaluation criteria are as follows. Grade A: No peeling at all. Class B: When the content is less than 10%, the ink adheres to the surface of the cellophane tape. Class C: Ink adheres to the cellophane tape surface at 10% or more.

(10) Weather resistance Sunshine weather meter The appearance after 240 hours was judged according to the following criteria.

Grade A: Almost no change in appearance is observed. Class B: slightly yellow. Class C: The appearance changes greatly.

Example 1 Polyethylene terephthalate as polyester A (intrinsic viscosity 0.63, melting point 257 ° C., silicon oxide particles: average particle size 1.2 μm, 0.3% by weight), and polyester B as isophthalic acid 15 mol% Polymerized polyethylene terephthalate (intrinsic viscosity 0.55, melting point 224 ° C., rutile titanium oxide particles: average particle size 0.3 μm, 10% by weight)
Are fed to separate extruders, melted at 280 ° C., then laminated in two layers (polyester A layer / polyester B layer = 2/1) with a feed block, discharged from a normal die, and then electrostatically printed. Meanwhile, the film was brought into close contact with a cooling drum to be cooled and solidified to obtain a cast film. Further, the film was longitudinally stretched 3.5 times at 95 ° C. and cooled, and then at 115 ° C., 3.7.
The film was transversely stretched twice, relaxed at 235 ° C. for 3 seconds by 3%, heat-treated and wound. The physical properties of the two-layer laminated film thus obtained are shown in Table 1. As can be seen from the table, although the weather resistance was slightly low, the embossability was good and no curling was observed.

Examples 2 to 6 Copolymerization, change of particles, surface wettability, optical density, etc., acrylic polymer film was laminated, a film was obtained in the same manner as in Example 1, and physical properties of the film were examined. .

The results are shown in Tables 1 and 2.

In Example 2, when the melting point of polyester B was changed and corona discharge treatment (E = 40) was performed, good ink adhesion and embossability were obtained, and no curling occurred.

In Example 3, when 15% of titanium oxide having an average particle size of 0.3 μm was contained in polyesters A and B, as shown in Table 1, good weather resistance and embossability were obtained, and curl There was no outbreak.

In Example 4, 10% of calcium carbonate particles having an average particle diameter of 0.8 μm were added to polyester A, and 2% by weight of a benzotriazole-based ultraviolet absorber was added to both surfaces of the polyester A to laminate a layer B having particles changed. When the film was formed, as shown in Table 2, weather resistance and embossability were good and curling did not occur, but blocking resistance decreased.

In Example 5, after the ink and adhesive were applied to the film of Example 2, a 15 μm polymethylmethacrylic resin film was laminated. As a result, the film of the present invention had excellent embossability and weather resistance.

Comparative Example 1 A film was obtained in the same manner as in Example 1 using only polyethylene terephthalate. The obtained film was significantly deteriorated in embossability.

Comparative Example 2 A biaxially stretched polyethylene terephthalate film had a melting point of 1
After thermally laminating the isophthalic acid-copolymerized polybutylene terephthalate cast film at 40 ° C., the embossability and the like were evaluated. As a result, the film was greatly curled after the embossing and printing could not be performed.

Comparative Example 3 In Example 1, the heat setting temperature was 200 ° C. and the relaxation was 0.
A film was obtained in the same manner as in Example 1 except that the percentage was changed to%.
The obtained film had deteriorated embossability.

[0053]

[Table 1]

[Table 2]

[0054]

The film of the present invention has excellent embossability because it is formed by laminating polyesters having different melting points and forming a layer that can be embossed by heat treatment, and is suitable as a film for laminating decorative sheets for building materials. Can be used for

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-52-23161 (JP, A) JP-A-7-90093 (JP, A) JP-A-7-89010 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (3)

(57) [Claims] 1. A polyester A having a melting point of 220 to 270 ° C.
A melting point of 150 to 2 on at least one surface of the layer (A layer)
A layer (layer B) composed of polyester B at 45 ° C. is laminated, and the sub-peak by DSC is in the range of −5 ° C. or higher of melting point of polyester B to −5 ° C. or lower of melting point of polyester A.
A rolled lengthened films that optical density is 0.2 or more
An easily embossable film which is 1.7 or less . 2. The surface roughness Ra of the A layer is 0.01 μm or more and 3 μm, and the leak tension of the B layer on at least one surface is 45.
It is dyne / cm or more, The easily embossable film of Claim 1 characterized by the above-mentioned. 3. easy embossing film to claim 1 or 2, characterized in that provided on at least one surface of the B layer of an acrylic polymer layer.