JPS6183399A - Base paper for impregnation - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an impregnated base paper for obtaining a resin-impregnated sheet for lamination having good flexibility, rta strength and opacity.

One field of decorative surface materials for building materials includes cylinder-pressure melamine decorative boards, low-pressure melamine decorative boards, and DAP decorative boards, all of which are made into decorative materials by impregnating base paper with resin and drying it, followed by hot-pressure molding. Recently, due to the development of resins, a method of manufacturing decorative pads that is paper-based but eliminates the entire hot-pressure molding process has been discovered, and it has become possible to easily and inexpensively process curved parts using the pasting method.

[Conventional technology]

For this purpose, the decorative sheet must have flexibility, interlaminar strength, and opacity. There are two factors that determine the characteristics of the decorative sheet: the impregnating resin and the impregnating base paper.

The flexibility and interlayer strength of decorative sheets are often determined mainly by the type and composition of the resin used. For example, if we use commercially available titanium paper as a base together with a thermosetting resin, urea resin, and a thermoplastic resin, an acrylic resin emulsion, a mixed system with the above resin weight ratio of 1=1 is the standard. In this case, increasing the amount of gold in the urea resin improves the interlaminar strength but decreases the flexibility, while the opposite property is dominated by gold when the mixture is reversed. For this reason, it can be seen that it is difficult to produce a decorative sheet that has both physical properties simply by using a resin composition alone.

When handmade paper made from unbeaten LBKP was used in place of all commercially available base paper, it was found that paper impregnated with acrylic resin emulsion alone had both flexibility and interlaminar strength. Ta.

However, the opacity of this impregnated paper is extremely poor, making it unsuitable for use as a building material. In order to solve these problems, the present invention was developed as a result of intensive research into base paper for impregnation.

[Problems to be solved by the present invention]

As mentioned above, the laminated decorative sheet has flexibility, two-layer strength,
Although opacity is necessary, I will add some explanation regarding this. Flexibility is required for laminating decorative sheets to curved substrates, but flexibility is not required after lamination. Therefore, it is sufficient that the decorative sheet retains its flexibility during the period in which it is manufactured and then laminated in a processing factory. Generally, this period can be considered to be within two months.

Furthermore, in order to impart flexibility, resins that inherently have flexibility are used, but water-based emulsion resins are generally used in consideration of operability. For this reason, the base paper for impregnation has a wet strength sufficient to withstand the impregnation process [generally U, 4 xy
/15-- or more], and at the same time, it is necessary to have all the voids that allow the resin emulsion particles to sufficiently penetrate into the paper layer.

The need for interlayer strength in decorative sorting is due to the following reasons. Decorative sheets are used as surface materials for furniture, wall materials, etc., so sellotape is used in general homes.

It is thought that attaching adhesive materials such as duct tape and adhesive hooks will naturally become a problem. If the decorative sheet itself is destroyed from within when such adhesives are removed, the aesthetic appearance will be completely destroyed. For this reason, it is necessary to have a strength that can at least withstand the force when peeling off the cellophane tape.

In order to sufficiently develop interlaminar strength, it is necessary for the impregnating resin to penetrate into the inside of the paper layer. In cases such as flat plates where flexibility is not so required, a water-soluble thermosetting resin is used in combination with the impregnating resin. In this case, the water-based tree 11tIT easily penetrates into the inside of the paper even if the first-layer base paper is relatively dense, so that interlaminar strength is easily obtained.

Next, regarding opacity, although decorative sheets are generally printed, there is little solid printing on the entire surface, and there are many patterns. In this case, if the opacity of the sheet is insufficient, the underlying color of the base material will show through in areas with little ink, and variations in the quality of the base material will change the design quality and impair commercial value.

The above-mentioned example of handmade paper corresponds to this. For this reason, it is necessary to impart opacity at the base paper stage, and in general, internal addition of rutile-type titanium dioxide, colored pigments, etc., which have good light resistance, is suitable for this purpose. When pigments such as these are internally added to base paper, sufficient attention must be paid to the yield since the pigment particles are smaller than the paper machine wire mesh.

The present invention is the first to disclose a resin-impregnated base paper that satisfies the above requirements.

The reality is that commercially available titanium paper is not sufficiently impregnated with emulsion type resin, and in order to maintain the desired glabellar strength, it is unavoidable to add water-soluble resin. This is thought to be because the paper layer structure of commercially available titanium paper is such that it prevents gold from penetrating the emulsion particles. That is, it is thought that this is because the pigment particles used are small and the pore diameter within the paper layer is small. -Many commercially available titanium papers have a pH of 7 or less, and when a dehydration condensation resin is used together as an impregnating resin,
Hydrogen ions from the paper act as a condensation catalyst in the condensation reaction, and when the decorative sheet is laminated to a base material, it is often condensed and hardened to the extent that it is not suitable for curved base materials.

The present inventors have discovered that the pigment particle size can be freely changed and the PHi of paper can be changed freely.
We focused on calcium carbonate as a substance that can be moved to a weak alkaline region and retard the curing of condensed resins.

Calcium carbonate is commercially available, and there are many types ranging from heavy to light1, and its particle size range is extremely flexible compared to other papermaking fillers or pigments. Therefore, when calcium carbonate is added internally to paper, the pore structure within the paper layer can be changed significantly depending on the particle size characteristics of the calcium carbonate used.

In order to add all calcium carbonate internally and to develop the full wet strength of the paper within a period that can withstand use, urea-based and melamine-based wet paper strength agents, which are condensation type resins, must be recycled.
Polyamide polyamine epichlorohydrin wet paper strength agents are suitable. This wet paper strength agent also acts as a retention aid for internally added pigments and is therefore suitable. Shikaji,
The amount used should be at least 0.00% of the pulp from the viewpoint of the desired wet strength and pigment wire yield.
The results of the study revealed that it is necessary to limit the content to a range of 1% or more and 2% or less. Some of the results are shown below.

Contains L-BKP and N-BKP in a total ratio of 85:15.

Beaten, Canadian Standard Freeness CC
8F) 40Um, beaten at 1 to z. Next, a polyamide polyamine epichlorohydrin wet paper strength agent manufactured by Dick Norcules Co., Ltd. under the trade name Kaimen 557-He was added in an amount of 6% to pulp. Furthermore, as pigments, titanium dioxide (trade name: R-3L) manufactured by Sakai Chemical Co., Ltd. and manufactured by Okutama Kogyo Co., Ltd. were used.

Light Cal product name Tama Pearl 222Hk 33% to pulp each
, 17% was added, and a test Fourdrinier paper machine was used to obtain a strain of 1 [
] Oy/m" paper was obtained. The pigment yield and wet strength of the paper are shown in Table 1, and it is clear from Table 1 that the above-mentioned usage amount range is suitable.

Table 1 When calcium carbonate is added internally, the base paper becomes bulkier than other pigments, making it possible to lower the blending ratio of the acrylic emulsion (kA), resulting in a more flexible decorative sheet. However, as the addition rate of calcium carbonate increases, the strength of calcium carbonate gradually decreases, and there is an upper limit to the amount of calcium carbonate used. In addition, since calcium carbonate has a lower refractive index than rutile titanium dioxide used in commercially available titanium paper, the amount of opacity reduced due to resin impregnation is large, so the amount used for calcium carbonate is determined from the viewpoint of opacity. There is also an upper limit.

- There is no particular lower limit to the amount used, as long as it exists in the base paper of the product, but if it is less than 2% in the paper, it is impossible to guarantee the content and stably manufacture it, both from the PH value of the paper and from the paper manufacturing technology. It is not easy, but 2% or more in paper is desirable.

We investigated the usage rate of calcium carbonate and the method of using it in combination with other pigments to satisfy these characteristics. Specifically, we created base paper with various pigment blending ratios and used it as a makeup sheet after the resin gold was submerged.
Under a pigment compounding ratio where the light reflectance (expressed as a binary value on a colorimeter) of the decorative sheet surface determined by preliminary study when attached to a black particle board using a K-vinyl acetate adhesive, is a factor of 94 or higher. The flexibility and interlayer strength of decorative sheets were investigated.As a result, the allowable total pigment ratio or the ratio of calcium carbonate to other pigments changes depending on the manufacturing method and particle size of calcium carbonate used, but the suitable The conditions for obtaining a good balance of physical properties are that the content of calcium carbonate is 2% or more and 25% or less,
It has been found that a range of 40% or less is desirable as the total pigment content. In addition, the base paper for impregnation may be printed before being immersed in resin, so printing suitability is required. In order to improve printability, it is common to use a machine calender or a super calender, and reducing the processing line pressure wK improves smoothness and printability. However, this is usually accompanied by a decrease in paper thickness and an increase in air permeability.

The decrease in paper thickness and the increase in air permeability are the result of a decrease in paper layer voids, and the permeability of the impregnating resin deteriorates, which are contradictory characteristics. For this reason, it is necessary to limit the calender or supercalender treatment to a range that does not impede resin permeability.
It is preferable to control the basis weight), and its 111 is 0.4
It was determined that the following is necessary. The results of the study are explained below.

Blended with L-BKP and N-BKP in a total ratio of 85:15,
Beating was performed with C8F 400zA Kl. Next, 0.7'%-fc of a polyamide polyamine epichlorohydrin wet paper strength agent, trade name Kaimen 557H, was added to the pulp, and titanium dioxide trade name (R-5L) and calcium carbonate trade name (Tama Pearl 222I ()) were added as pigments. A test Fourdrinier paper machine was used to obtain a base paper with a basis weight of 100 y/G2 paper, 14 titanium dioxide, 1 paper, carbonate strength, 7 rams, and 5 parts.This base paper was subjected to an off-machine calender to change the linear pressure. Papers with different specific air permeability were prepared and subjected to resin permeability tests.

The impregnating resin liquid is manufactured by Nichiryo Kagaku Kogyo Co., Ltd., acrylic resin (emulsion) product name is 410 and urea resin surface product name is F-4.
00, the solid content ratio was 1:1, and the liquid concentration was 4%. A piece of paper measuring 5 cm x 5 cm was floated on the resin liquid surface, and the time required for the resin liquid to completely penetrate was measured.

The test was conducted under an environment of 20'C and 65% RH. If the penetration time is longer than 60 seconds, the operating speed of the impregnating machine will be significantly reduced. If the emulsion does not penetrate from the top surface of the paper, the interlayer strength of the impregnated paper will be insufficient and the penetration will be slow. It was rated as a gender failure. The results are shown in Table 2, and the resin permeability deteriorated as the specific air permeability increased, and papers with a specific air permeability of more than 0.4 were rejected for permeability.

Table 2 Relationship between base paper air permeability and resin permeability Also, extraction PH of base paper with internal addition of calcium carbonate (JIS, P81
No. 33) is in the weak alkaline range, and it was revealed that the impregnated paper had excellent flexibility, probably because it delayed the curing of the impregnating resin, and maintained its flexibility for at least about two months.

The present invention will be described below with reference to examples, but is not limited thereto.

Example T, -BKP and N-BKP are blended in a ratio of 85:15,
It was beaten at csp400mA at 1. Next, a polyamide polyamine epichlorohydrin wet paper strength agent (trade name: Kaimen 557Hw) to pulp L (1.7%), titanium dioxide (R-3L) and light calcium carbonate (Tamavar 222H), or titanium dioxide and heavy calcium carbonate (three groups) Niscalon #100 (manufactured by Seifun Co., Ltd.) was added in the above order, and the basis weight was 100 y/mm using a test Fourdrinier paper machine.
m” paper was made.

The pigment ratio in the paper was 40% or less, and the pigment ratio was added so that the light reflectance of the resin-impregnated paper was 94 coefficients or higher.

Further, the machine calender pressure was adjusted so that the specific air permeability was 0.4 or less.

The physical properties of the obtained base paper and resin-impregnated paper were measured. The impregnating resin liquid is acrylic resin (E-410) and urea resin (F
-4003 and solid content ratio of 1:1, liquid concentration 'fr, 40
%. The resin impregnation rate expressed by the following formula was controlled to well 67 to 68.

Drying after impregnation was performed in an open state at 165° C. for 1 minute.

The results for 2 Kasa are summarized in Table 6.

Comparative Example 1 Using the same valves, pigments, and paper machine as in the example, a base paper in which only the pigment percentage in the paper was 4% or more was obtained. Table 6 shows their physical properties.

Comparative Example 2 Paper was made under the conditions of Example without using calcium carbonate. For some items, talc (Nippon Talc Co., Ltd.)
Manufactured by EilWB J.

Table 6 shows their physical properties.

Note that the physical property values were measured according to the following method.

Paper quality measurement environment: J Engineering s-: p8111 Pigment ratio in paper
...Absolutely dry paper'! The paper was incinerated at 550° C. for 2 hours and at 950° C. for 2 hours, and the percentage of pigment in the paper was calculated from the respective ash contents and the ignition loss rate of the pigment alone.

Specific air permeability, , , J, TA, PP engineering N (L 5-B
Regulated air permeability down payment divided by JIS P8124 regulated basis weight.

i) Extraction PH--JISP8133 Cellotape resistance test... Commercially available cellophane tape (Sekisui Co., Ltd. 15wn) was applied to impregnated paper.

(width) firmly adhered, Paper surface when peeled off at once fluff, and cello Attaching the impregnated paper to the tape side The condition was visually determined.

×: Things that cause delamination △: There is fluff on the paper surface. thing O: Unchangeable rated it as.

Rigidity of impregnated paper: Manufactured by Kato Iron Works Co., Ltd.

Product name KKS-FB2 Initial test using pure bending tester Total stiffness measurement (unit: ycm/ct) did.

It is clear from Table 6 that the base paper of the example has the characteristics for obtaining a resin-impregnated sheet for building materials that has both good flexibility, interlayer strength, and opacity.

That is, in the case of the base paper shown in Comparative Example 1 with a pigment ratio of 40 or more, the emulsion type resin did not permeate the upper surface 1 of the base paper in the dark fat penetration test, so the evaluation was failed. The fc# fat-impregnated paper obtained from these base papers broke from within the paper layer in the 111 Cellotape test.

In Comparative Example 2, fuzzing was observed on the paper surface in the cellophane tape resistance test.

'tfc, the rigidity of the resin-impregnated paper was high (initial rigidity value of 15 or more), probably because the base paper PH was weakly acidic, and it was not easy to attach the paper to a curved paper.

On the other hand, the base paper shown in the example had good results in the Sellotape resistance test, had sufficient layer and interlayer strength, and had a lower rigidity value than Comparative Example 2, making it easy to attach to a curved paper. Although the rigidity slightly increased two months after the impregnated paper was manufactured, the work of laminating it to the curved base was as easy as immediately after manufacturing.

J so　1″　s′; Procedural amendment November 2, 1982

Claims (1)

[Claims] 1 0.1 to 2% by weight of polyamide polyamine epichlorohydrin wet paper strength agent, 25% by weight of calcium carbonate
The total weight percentage of pigments including the following and adding pigments mainly composed of rutile titanium dioxide is 40% or less, the relative air permeability of the base paper is 0.4 or less, and the pH of the extract is 7.5 ~
Base paper for impregnation in the range of 9.5.