JP3145082B2 - Polyester resin decorative plywood and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester resin decorative plywood and a method for producing the same, and more particularly, to a JAS standard specially processed decorative plywood in which delamination near the surface of a printed decorative paper is eliminated. And a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, polyester resin decorative plywood has been
An adhesive of urea resin and vinyl acetate is mixed at an appropriate ratio on a base material surface such as a veneer plywood and applied with a spreader, and then a printed decorative paper is placed thereon.
It is manufactured by bonding with a hot press of Kg / cm ² , and then applying a coating resin containing an unsaturated polyester resin as a main component on the surface of the decorative paper, followed by curing treatment.

[0003] In this case, when a vinyl compound such as styrene is mixed with an unsaturated polyester resin and cured, a curing treatment is generally performed under heating. When a curing agent or an accelerator as a polymerization initiator is added, the mixture is heated in an initial stage for a short time (about 1 to 3 minutes) to bring it into an undercured state, and thereafter, the atmosphere is at room temperature (25 ° C.). The curing process is performed by leaving the device under the condition for about one hour. It is known that such a curing treatment results in a resin having a three-dimensional network structure in which cross-linking occurs between molecules.

[0004] Such a polyester resin decorative plywood has the advantage that the manufacturing process itself is relatively simple and can be easily manufactured without requiring special equipment. In addition, it is easy to apply thick coating resin on decorative paper and the finish is excellent, and after curing, the coating film has good fluffiness, gives the pattern depth and gives a good appearance, surface hardness, heat resistance Because of their excellent properties, they are widely used in furniture and building materials (especially walls, floors, ceilings, doors, partitions, etc.).

[0005] However, when a printed decorative paper is adhered to a base material surface such as veneer plywood and bonded, a mixture of urea resin and vinyl acetate at an appropriate ratio is used as the adhesive. Polyester resin decorative plywood often did not meet the JAS specially processed decorative plywood standard test. Here, JAS standard special processing cosmetics
For boards, 1st, 2nd, 3rd, F type, FW type, W
Type and SW type, these JAS special
As a standard test for processed decorative plywood, (1) Immersion peeling test
Test, (2) plane tension test, (3) moisture content test, (4)
(5) Water resistance test, (6) Moist heat test,
(7) Abrasion test, (8) Scratch hardness test, (9) Impact
Test, (10) Discoloration test, (11) Contamination test, (12)
Alkali resistance test, (13) Acid resistance test, (14) Thinner resistance
-It is required to pass all or part of the test
You. In particular, for JAS FW type, see (1) above.
(11) (except (6))
It is required that (1) immersion peel test,
According to the plane tension test of (2), paper near the gravure printing ink layer of the decorative paper causes delamination, and JAS F
Frequent failure to pass the W-type compliance test has occurred.

As a result of various studies as to the cause, ordinary decorative paper (gravure printing paper or the like) has a weight of 60 g / m ^{2 to} 80 g / m ^2.
The paper quality is thick, and a considerable amount of adhesive (15 g or more per 30 cm x 30 cm) is required to penetrate the urea resin and vinyl acetate or other isocyanate-based adhesives to the printing interface. Therefore, ordinary adhesives are as small as about 6 g per 30 cm × 30 cm. Therefore, it is considered that in such a thick paper decorative paper, the adhesive is bonded between the paper layers by an uneven physical anchoring effect (anchor effect) even when hot pressed.
Further, by impregnating the polyester and the plywood from the surface of the bonded paper and curing the paper and the plywood, the resin is impregnated and cured in the uneven portions between the paper layers, thereby performing physical bonding called an anchor effect. Therefore, unlike the adhesive of the chemical reaction, the adhesive force between the paper and the resin is fundamentally different from the adhesive of the present invention.
Somehow passed the SFW standard tensile test, but did not break the material.

[0007]

Therefore, it is conceivable to reduce the paper thickness of the decorative paper (gravure printing paper or the like) to 20 g / m ^{2 to} 30 g / m ² , but an appropriate ratio of urea resin to vinyl acetate can be considered. The adhesive mixed in the above has no affinity with the vehicle of the printing ink, so even if the adhesive comes to the vehicle interface near the printing layer, no chemical reaction occurs with the vehicle and at the same time the unevenness of the paper layer due to the thin paper Is very small and physical bonding of the anchor effect is not possible. Under such circumstances, the object of the present invention is to provide a polyester resin compatible with specially processed decorative plywood such as JAS FW type, which prevents delamination of decorative paper near the surface near the printing ink layer of polyester resin decorative plywood subjected to gravure printing or the like. It is an object of the present invention to provide a resin decorative plywood and a method for producing the same.

[0008]

As a result of various studies to solve the above-mentioned problems, the present inventor has found that a printing ink vehicle is used as an adhesive that penetrates and penetrates from the plywood surface to the printing surface of the decorative paper when the decorative paper is attached. It has been found that it is effective to solve the problem to select and use a special adhesive having an affinity for the present invention, and completed the present invention.

That is, the polyester resin decorative plywood according to the first aspect of the present invention has a thickness of 20 g / m ² , in which the vehicle is printed with an ink comprising a nitrocellulose derivative.
30 g / m ² of decorative paper is adhered to plywood with an aqueous polymer / isocyanate adhesive, and the surface of the decorative paper is coated with a room-temperature-curable coating resin containing unsaturated polyester as a main component. It is suitable for plywood.

In the method for producing a decorative plywood of a polyester resin according to the second aspect of the present invention, when the printed decorative paper is attached to the surface of a base material such as a plywood, the affinity with the vehicle of the printing ink. After the adhesive is penetrated from the contact surface with the plywood to the printing interface of the decorative paper by using the adhesive having the adhesive, and then adhered, the room temperature curing type coating mainly containing unsaturated polyester is applied from the decorative paper. The resin is applied and cured.

In a preferred embodiment of the production method of the present invention, an aqueous polymer / isocyanate-based adhesive is used when the vehicle of the printing ink comprises a cellulose derivative, and the adhesive is applied from the surface of the base material to decorative paper. Paste with a hot press so that it penetrates and penetrates to the printing interface of
Preferably, the adhesive is completely solidified in conjunction with the curing treatment. In addition, the curing treatment is performed in the tunnel furnace after the under-curing state, for about 1 hour, while being transferred by the conveyor, and the section of about 20 to 40 minutes in the former stage is subjected to a high-temperature treatment in a heating atmosphere of about 30 ° C. or more. It is particularly preferable to cure the cured state and the remaining time section in the latter stage in a low-cured state at room temperature.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below in detail. Examples of the base material used in the present invention include a wood board and a veneer plywood which are formed by applying and impregnating a formaldehyde-based resin adhesive (mainly an initial condensate) or the like on the bonding surface of the material and bonding by a curing treatment under heat and pressure. Wood-based support materials such as hardboard and particleboard are generally suitable, but other cardboard, gypsum board, various cement boards, steel sheets and the like can also be used. Particularly preferred substrates are plywood, particle board, veneer plywood and the like.

The decorative paper to be adhered to such a substrate is one that optically and physically shields the substrate layer and performs the decorative function of a decorative plate, and usually uses highly purified pulp as a raw material. For example, titanium paper into which a large amount of pigment, particularly titanium oxide is incorporated, is preferable, but thin paper, vinyl chloride sheet and the like can also be used. Decorative paper thickness is usually 60g / m ² ~80g / m ² have been used, in the case of the present invention is not a physical bonding by adhesive anchoring effect, a chemical reaction In order to adhere with
Since the thickness of a conventional thinner 20g / m ² ~30g / m ² can be preferably used, the cost of that amount decorative paper is advantageously requires only inexpensive.

The present invention is directed to a decorative paper on which gravure printing, offset printing, or the like has been performed. The printing ink is mainly composed of an organic pigment or a part of an inorganic pigment and a viscous liquid (vehicle) for keeping the pigment dispersed, and to which water or a volatile organic solvent, a drying accelerator, various regulators, etc. are appropriately added. Have been. Here, various vehicles are conventionally known, and examples thereof include mineral oil, vegetable oil, synthetic drying oil, resins, and cellulose derivatives. Although not particularly limited in the present invention, an example in which a cellulose derivative is used as a vehicle of a gravure printing ink will be described below.

The cellulose derivative may be any soluble cellulose ester or ether, preferably nitrocellulose, ethyl cellulose and the like. Particularly preferred is nitrocellulose, which is a reaction product in which three hydroxyl groups in glucose residues are substituted on average from 0 to 3 as shown in the following general formula, and has a nitrogen content of 11 to 12%. Is easily dissolved in a mixed solvent of alcohol and ether and an organic solvent of esters and ketones, and is most preferable as an ink for gravure printing. [C ₆ H ₇ O ₂ (OH) ₃ ] n + HNO ₃ → [C ₆ H ₇ O ₂ (OH)
_3-x (ONO ₂ ) _x ] n (where x is the degree of substitution and n is the degree of polymerization)

In the present invention, decorative paper, which has been subjected to gravure printing or the like with an ink containing a cellulose derivative as a vehicle, is adhered to the surface of the base material such as the plywood with an adhesive having an affinity with the vehicle of the ink. In particular, it has the greatest features. Here, the adhesive having an affinity for the vehicle of the ink may be any adhesive that easily penetrates at the stage of applying the adhesive, easily dissolves each other, or undergoes additional bonding (polymerization) to easily become a polymer. In the case of the above nitrocellulose derivative,
It is sufficient to select an adhesive having an affinity that is easily bonded to a hydroxyl group in a glucose residue by a chemical reaction such as addition polymerization, hydrogen bond (urethane bond, urea bond, etc.), and covalent bond. Preferred examples thereof include an adhesive, an aqueous epoxy adhesive, and the same unsaturated polyester adhesive of a room temperature curing type described later.

It is particularly preferable that an aqueous polymer solution (solution A) such as polyvinyl alcohol or saturated polyester generally having an OH group and an isocyanate compound (solution B) are mixed at an appropriate ratio, and the reaction polymer is cured. It is desirable to use an isocyanate-based adhesive (polyurethane solution adhesive). Here, the chemical reaction mechanism of the aqueous polymer isocyanate-based adhesive will be described below. Isocyanate compounds, such as 4,4 ′ diphenylmethane diisocyanate (MD
I) and a hydroxyl group-containing polyvinyl alcohol (PVA) or moisture form a bond (urethane bond, urea bond, further, buret bond or allophanate bond) by the following reaction mechanism, and exhibit an adhesive function.

MDI (hereinafter abbreviated as R-NCO)
Reaction of water with R-NCO + H ₂ O → R-NH ₂ + CO ₂ ↑ (decarboxylation) R-NCO + R-NH ₂ → R-NHC (ＯO) NH-R
(Urea bond) R-NHC (= O) NH-R + R-NCO → R-NHC (=
O) N (CONHR) -R (burette bond)

Reaction of MDI with -OH group of PVA or wood cellulose (hereinafter abbreviated as HO-R ') R-NCO + HO-R' → R-NHC (= O) OR '(urethane bond) ) R-NHC (= O) OR ′ + R-NCO → RN (CON
HR) C (= O) OR '(allophanate bond)

From the chemical reaction mechanism, it can be seen that the aqueous polymer / isocyanate adhesive has an affinity to form a hydrogen bond via an -OH group when the vehicle of the printing ink is a cellulose derivative. In this case, it is preferable to hot press the printed decorative paper on the surface of the base material using an aqueous polymer / isocyanate adhesive. By such hot pressing, the adhesive easily penetrates from the substrate surface to the printing interface of the decorative paper.

The hot pressing conditions are as follows:
It is preferable that the temperature is 110 ° C., the pressure is 3 to 5 kg / cm ² , and the time is about 10 to 60 seconds. In such a hot press, the aqueous polymer / isocyanate-based adhesive has an affinity for the vehicle of the printed ink, and therefore easily penetrates and penetrates from the base material surface to the printing interface of the decorative paper to form a chemical bond. It is preferable to apply a room-temperature-curable coating resin containing an unsaturated polyester and a vinyl compound as a main component from the decorative paper after being attached by the hot press, and to completely solidify the adhesive together with the curing treatment. Here, as the room temperature curing type coating resin used in the present invention, an unsaturated polyester and a vinyl compound such as styrene copolymerizable therewith are blended, and a curing agent, an accelerator and other usual optional additives are added thereto. A room-temperature-curable unsaturated polyester resin liquid containing an agent and the like.

The unsaturated polyester is a liquid obtained by heating an unsaturated dicarboxylic acid such as maleic anhydride and a glycol such as ethylene glycol and performing a polycondensation reaction. The copolymerizable vinyl compound such as styrene is mainly composed of a styrene monomer which is liquid at room temperature, but is used by blending methyl methacrylate, methyl acrylate, vinyl acetate, vinyl toluene and the like. You may. The mixing ratio of these vinyl compounds to the unsaturated polyester is not particularly limited as long as it is within a range usually used.

The curing agent used as the polymerization initiator includes organic peroxides such as benzoyl peroxide, t-butylperoxybenzoate, methyl ethyl ketone peroxide, and lauroyl peroxide. In addition, as the accelerator mixed with the curing agent, cobalt naphthenate, aromatic amines such as dimethylaniline and triphenylamine can be used. The amount of these curing agents and accelerators to be added to the unsaturated polyester resin liquid is not limited as long as it is within a range usually used.

In particular, the time when the curing agent is mixed with the mixture of unsaturated polyester and styrene is as follows, immediately before flowing the coating resin onto the printed decorative paper attached to the base material.
Alternatively, it is preferable to add and mix when flowing. To apply the coating resin on decorative paper, flow coater method,
There are a film coating method, a pressing method and the like, and there is no particular limitation.
Of these, the film coating method is preferred, and the film coating method will be described below.

In this case, the base material (for example, 2.5 mm × 920 mm × 1830 mm) to which the decorative paper is adhered is moved on the endless conveyor or for a predetermined time (for example, 1 mm).
(0 to 30 seconds) In a stopped state, a room-temperature-curable coating resin is usually placed in a circular shape at about 300 to 500 g on a central portion near 300 mm from the front end position of the base material on the pattern paper, and the upper surface is covered with a film. The film used here is preferably cellophane (viscose film), vinylon, tetron (polyester synthetic fiber), or the like, having a certain degree of heat resistance.

In order to cover the upper surface of the flowing coating resin with the film, it is necessary to overlap the framed film in a state of being stretched in advance so that the film surface is not wrinkled, and to fix the end with a jig. desirable. After that, it is necessary to apply a pressing force with a rubber roll from above the stacked film, thereby making the film and the coating resin adhere to each other while uniformly spreading the coating resin on the pattern paper of the base material, and removing air bubbles.

In the present invention, the coating resin is evenly spread on the patterned paper of the base material and cured in a state in which the coating resin is brought into close contact with the coating film. Here, at the start of the curing treatment, infrared rays are radiated to the coating resin as in the past, and the temperature is 40 ° C. or less, preferably 3 ° C. or less.
Heated to about 8 ° C for about 1 to 3 minutes and started to cure
It is preferable to set the gel under cure state in a stage . In the present invention, in particular, as the curing treatment conditions after the gel undercure state, a high cure state in which the curing rate is increased under heating at about 30 ° C. or more or under ultraviolet irradiation, and a low cure state in which the curing rate at normal temperature is reduced. It is preferable to cure in two stages of the state. The upper limit of the heating temperature in the high cure state is not particularly limited as long as the base material is not deformed or wrinkles are not generated in the film, and is not particularly limited, but is usually 80 ° C. or lower, and more preferably 40 to 60 ° C.

Here, the particularly preferred curing treatment conditions of the present invention are as follows: the painted gel- under-cured decorative board is continuously transferred while being placed on an endless conveyor in a tunnel furnace for about 1 hour. The curing process is performed in a high curing state under a heating atmosphere of about 30 ° C. or more in a section for about 20 to 40 minutes in a first stage, and in a low curing state in a normal temperature atmosphere in a remaining section in a subsequent stage. . This has the effect of reducing the generation of malodorous substances such as styrene, so that the polyester resin decorative plywood of the present invention can be continuously mass-produced.

The heating means at this time is not particularly limited, but may be infrared radiation heating using electricity or gas as a heat source, an ordinary electric heater with a thermostat, or a combustion type zet heater such as gas or kerosene. .
It is recognized that the polyester resin decorative plywood cured in the two stages has significantly reduced generation of residual styrene as compared with that obtained by the curing treatment only at room temperature. It is considered that this is because at least the curing reaction by the cross-linking between styrene and the molecule under the heating atmosphere in the preceding stage efficiently proceeded.

[0030]

The present invention will be described below with reference to specific examples. Example 1 As a base material, the thickness of the top plate was 0.55 mm, and the thickness of the core plate was 1.25 m.
The plywood for the base plate (length 1830 mm × width 920 mm) made of Lauan material having a thickness of 0.65 mm was used.
A two-part adhesive (AU7008FK / AUH-1: manufactured by Aika Kogyo Co., Ltd.) composed of an aqueous polyvinyl alcohol (PVA) -based base material / polyisocyanate (MDI) -based curing agent was used as an adhesive on the surface of the base material using a spreader. In a state of being applied, 23 g / m ² of printing decorative paper (thickness: about 30 μm; manufactured by Dai Nippon Printing Co., Ltd.) on which a grain pattern is gravure-printed with a printing ink using nitrocellulose as a vehicle is applied.
Attachment was performed with a hot press at 6 kg / cm ^{2 for} 20 seconds. In this state, the adhesive had not been completely solidified yet.

While the base material on which the decorative paper is stuck is sequentially placed on a belt conveyor and moved, 350 g of a room-temperature-curable coating resin liquid is transferred onto each decorative paper, and the decorative paper layer is removed while defoaming. In addition, it flowed so that the thickness of the top plate was about 0.6 mm. Here, the room temperature-curable coating resin liquid is based on 100 parts by weight of an unsaturated polyester resin (trade name: Ester, manufactured by Mitsui Chemicals, Inc.) in which 35 wt% of styrene and 0.18 wt% of cobalt naphthenate are mixed as an accelerator. MEK peroxide (trade name, manufactured by NOF CORPORATION; Permec) as a catalyst was blended at a ratio of 1 part by weight.

A vinylon film with a frame is overlaid on the surface of the coating resin, and the film and the coating resin are spread while applying a pressing force with a rubber roll on the film while uniformly spreading the coating resin on the pattern paper. Air bubbles were removed by close contact. Next, radiating infrared radiation energy toward the coating resin liquid for only about 1 minute, heating it to about 38 ° C, transferring the decorative plate in gel-under-cured state to the endless conveyor, and continuously transferring it in the tunnel furnace To
A kerosene-burning type z-heater is installed as a heating source in the first half of the section for about 30 minutes, and is cured in a high-cured state under a heating atmosphere of about 45 ° C. After curing in a low-cured state under normal temperature atmosphere, the coated film is separated to cure the smooth polyester resin layer on the decorative paper on the surface and obtain a beautiful polyester resin decorative plywood integrated. Was done.

The obtained polyester resin decorative plywood was subjected to the following JAS (Japanese Agricultural Standards for Special Plywood): (a) a plane tensile test, (b) a dip-peeling test, and other tests. Was also confirmed to be compatible with JAS FW type specially processed decorative plywood. (A) Flat Tensile Test A test piece was cut into a size of 5 cm square, and the surface was lightly sanded. Then, a 2 cm square iron jig was bonded with cyanoacrylate, and a cut was made around the base plate to a depth reaching the plywood. After that, a flat tensile test (fixing the test piece and metal plate to the chuck, 600 K / min in a direction perpendicular to the bonding surface)
The maximum load was measured at the time of peeling or breaking at a load speed of gf or more. (Test result) Maximum value: 7.0 Kgf / cm ² (100) However, parentheses indicate the percentage of material fracture. Minimum value: 4.5 Kgf / cm ² (100) Average value: 5.8 Kgf / cm ² ( 100) According to the JAS FW type standard, if the average value of the adhesive force of the test pieces taken from the same sample plywood is 4 kgf / cm ² or more, it passes the conformity standard. Therefore, the product was subjected to a five-piece test in a tensile test, and it was confirmed that the adhesive strength was 4 kgf / cm ² or more and the material fracture rate was 100%, which was no problem.

(B) JAS class 2 immersion peel test A test piece was cut into a size of 7.5 cm square,
After immersing in warm water of 2 ° C. for 2 hours, drying at 60 ± 3 ° C. for 3 hours. (Test Results) Fifteen test pieces were tested, but none of them was peeled off, and it was confirmed that there were no abnormalities and that they conformed to the JAS standard. (C) Other JAS tests-In the water content test of (3), JA was 7.8 to 8.5 (%).
Conforms to 13% or less of S standard. In the cold repetition B test in (4) and the water resistance B test in (5), the test piece conformed to the JAS standard (no cracks, blisters, peeling, and significant discoloration and gloss change on the surface of the test piece).・ Other tests ① Wear B test of (7), pull of (8)
Hardness B test, impact B test of (9), fading B of (10)
It was also confirmed that the test and the contamination B test (11) in (11) were all compatible.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the adhesive on the substrate surface was changed to an adhesive (manufactured by Nishi Nihon Makeup Plywood Co., Ltd.) in which urea resin and vinyl acetate were mixed at 50% each. By performing the same treatment as in the example, a polyester resin decorative board was obtained. As a result of performing the same JAS (Japanese Agricultural Standard for Special Plywood) test on the obtained decorative board as described above, (a) in the plane tensile test, 20 out of 20 test variables were incompatible. (B) In the two-class immersion peel test, 1 out of 20 test variables was used.
Nine were non-conforming. As a result of checking these incompatible test pieces, it was confirmed that the decorative paper close to the printing ink layer of the decorative paper had peeled between layers.

[0036]

As described above, according to the present invention,
Printing decorative paper prior thinner 20g / m ² ~30g / m ² in thickness is advantageous in terms of cost of the decorative paper since that may be used. In addition, a special adhesive that has affinity for the printing ink vehicle penetrates and penetrates from the plywood surface to the gravure printing surface of the decorative paper when the decorative paper is attached, resulting in the polyester resin layer being hardened and integrated. The delamination of the decorative paper close to the printing ink layer of the resin decorative board is prevented, and a sheet that is compatible with JAS standard specially processed decorative plywood can be easily manufactured.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B27M 3/00 B27D 5/00 B32B 21/06

Claims (5)

(57) [Claims] 1. A thickness of 20 g / m ^{2 to} 30 g printed with an ink comprising a nitrocellulose derivative in a vehicle.
/ M ² of a decorative paper is bonded to a plywood with an aqueous polymer / isocyanate adhesive, and the surface of the decorative paper is coated with a room temperature-curable coating resin mainly composed of unsaturated polyester .
A polyester resin decorative plywood suitable for specially processed decorative plywood, such as JAS FW type, which prevents delamination on the surface of decorative paper . 2. When the printed decorative paper is attached to the surface of a base material such as plywood, an adhesive having an affinity for a vehicle of the printing ink is used, and the decorative paper is printed from a contact surface with the plywood. Manufacturing the polyester resin decorative plywood, characterized by applying a normal-temperature-curable coating resin containing unsaturated polyester as a main component from the decorative paper and curing after applying the adhesive to the interface and permeating the adhesive. Method. 3. An aqueous polymer / isocyanate adhesive is used when the vehicle of the printing ink comprises a cellulose derivative, and hot pressing is performed so that the adhesive penetrates from the surface of the base material to the printing interface of the decorative paper. 3. The method for producing a decorative plywood of a polyester resin according to claim 2, wherein 4. The curing treatment is to reduce the coating resin to about 40 ° C. or less.
Performs tunnel furnace in the following <br/> later by heating for 1 to 3 minutes and the gel under curing conditions in about 1 hour before and after over conveyor transport, about 30 ° C. The interval of the preceding approximately 20 to 40 minutes
The polyester resin decorative plywood according to any one of claims 2 to 3, wherein the curing treatment is performed in the high curing state under the above-mentioned heating atmosphere and in the low curing state under the normal temperature atmosphere in the remaining time section in the latter stage. Method. 5. The printed decorative paper has a thickness of 20 g.
/ M ² to 30 g / m ² process for making a polyester resin decorative plywood according to claim 2, wherein.