JP2005154979A - Neutral paper for joining metal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a neutral paper sheet for joining a metal capable of surely preventing issues caused by the degeneration of a metal part in using metal-joined paper as a substrate for an electronic part and having a metal surface or metal plated surface, and a method for producing the same. <P>SOLUTION: This neutral paper sheet for joining the metal used for joining the meatal with the paper sheet is provided by containing 0.2-2.0 mass% cationic starch, 0.2-2.9 mass% slip-preventing agent and 0.1-0.4 mass% releasing agent and also ≤200 ppm aluminum sulfate. The method for producing the neutral paper sheet for joining the metal comprises beating a raw material pulp so that the water filterability of the raw material pulp becomes within a specific range and also adding the cationic starch, slip-preventing agent and releasing agent in specific ratios. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a neutral metal interleaving paper and a method for producing the same. More specifically, the present invention relates to a neutral metal interleaving paper that can suppress corrosion and alteration of a metal portion when used for a process interleaving paper or a product interleaving paper for a substrate having a metal surface or a metal plating surface, and a method for producing the same.

  Interleaf paper is used for protecting various substrates. Recently, it is important as a protective material (process slip sheet or product slip sheet) for a substrate for electronic parts having a metal surface or a metal plating surface exemplified by a lead frame or a shadow mask.

  In general, in order to produce interleaving paper, a method of adding a sulfuric acid band in the process of paper making is adopted for the freeness of raw pulp, chemical fixability on the interleaving paper surface, and prevention of pitch defects. (Patent Document 1).

  However, if a slip sheet made by adding a sulfuric acid band is used as a base paper for electronic parts (so-called neutral metal slip sheet), the metal part is affected by the moisture in the slip sheet and the sulfate ions of the sulfate band. As a result, deterioration such as corrosion and discoloration occurs, and the performance of electronic components is impaired.

  In order to improve such a problem, the filler paper is not included in the slip sheet, the sulfate ion concentration and the chloride ion concentration in the slip sheet are in a specific range, and the SBR or acrylic synthetic of a specific Tg is provided on both sides of the slip sheet. A slip sheet in which the smoothness of the surface of a slip sheet obtained by applying a resin and calendering is in a specific range has been proposed (Patent Document 2). In this proposal, a filler such as a sulfuric acid band is not added in the process of making a slip sheet.

  However, when paper is made without adding any sulfuric acid band, the freeness of the raw pulp becomes unstable, making it difficult to make the paper stably. In addition, the properties of the interleaving paper surface are non-uniform, making it difficult to obtain interleaving paper of good quality.

Furthermore, recently, the required characteristics for electronic parts have become more sophisticated. For example, when the above-mentioned proposed slip sheet is used as a process slip sheet or product slip sheet for a base material for electronic components, copper circuit or silver plating is used in a high humidity atmosphere. Discoloration and alteration of the circuit part cannot be completely prevented. For this reason, there is a demand for a neutral metal interleaving paper that does not cause problems due to discoloration and alteration of the metal part. In addition, there is a demand for a method that can stably produce such slip sheets.
JP 07-1119075 A (Claims) JP 2000-303383 A (Claims)

  As a result of various studies to solve the above-mentioned problems, the present inventors can control the drainage and the dryer peelability by blending the cation starch, the anti-slip agent and the release agent at a predetermined ratio to make paper, and the efficiency. I have found that I can make metal slips well.

  Therefore, the present invention can solve the above-mentioned problems, and when used as a base paper for electronic parts having a metal surface or a metal plating surface, a neutral metal that can surely prevent problems due to alteration of the metal part. It is an object to provide a slip sheet and a manufacturing method thereof.

  The present invention for solving the above problems is described below.

    [1] In the neutral metal interleaving paper used for the metal interleaving paper, the neutral metal interleaving paper contains 0.2 to 2.0 mass% of cationic starch and 0.2 to 2.0 antislip agent. Neutral metal interleaving paper characterized by containing 0.1% by mass to 0.1% by mass of a release agent and 200 ppm or less of aluminum sulfate contained in the neutral metal interleaving paper. .

    [2] The neutral metal interleaving paper according to [1], wherein the content ratio of chlorine contained in the neutral metal interleaving paper is 200 ppm or less in terms of chlorine ion concentration.

    [3] The neutral metal interleaving paper according to [1] or [2], which is used for process interleaving paper or product interleaving paper for electronic component lead frames.

[4] A method for producing a neutral metal interleaving paper in which the aluminum sulfate in the interleaving paper is 200 ppm or less in terms of sulfate ion concentration, and the raw pulp is adjusted so that the freeness of the raw pulp is in the range of 300 to 550 cm ^3. Beating, and water slurry of raw pulp, 0.2 to 2.0 mass% of cationic starch, 0.2 to 2.0 mass% of anti-slip agent, and 0.1 to 0 of release agent in the slip sheet A neutral metal interleaving paper, characterized in that it is added so as to be contained at a ratio of 4% by mass, aluminum sulfate is not added, and the paper slurry is made while maintaining the pH of the aqueous slurry of the raw pulp in the range of 7-8. Production method.

  When the neutral metal interleaving paper of the present invention is used for process interleaving paper or product interleaving paper of a base material having a metal surface or metal plating surface (for example, a base material for an electronic component exemplified by a lead frame or a shadow mask) Corrosion and alteration of metal parts can be suppressed. Moreover, according to the manufacturing method of the neutral metal interleaving paper of this invention, the neutral metal interleaving paper excellent in characteristics, such as smoothness, can be manufactured efficiently.

  Hereinafter, the present invention will be described in detail.

[Neutral metal slip]
The neutral metal interleaving paper of the present invention contains 0.2 to 2.0 mass% of cationic starch, 0.2 to 2.0 mass% of anti-slip agent, and 0.1 to 0. The aluminum sulfate contained at a ratio of 4% by mass and contained in the neutral metal interleaving paper is 200 ppm or less.

  When the concentration of aluminum sulfate in the neutral metal interleaving paper exceeds 200 ppm, when the interleaving paper is used as a process interleaving paper and / or product interleaving paper for electronic parts, the metal portion of the lead frame, particularly copper or Corrosion or alteration of parts with silver.

  For this reason, when making the neutral metal interleaving paper of the present invention, aluminum sulfate (for example, sulfate band) is not added.

  Thus, in the present invention, an additive such as a sulfuric acid band is not used during papermaking, but in order to perform papermaking stably, an additive comprising a cationic starch, an anti-slip agent and a release agent is used for making a predetermined amount of papermaking. Add at the time. The addition amount of these additives is 0.2 to 2.0 mass% for the cationic starch, 0.2 to 2.0 mass% for the anti-slip agent, and 0.1 to 0.4 mass% for the release agent in the slip sheet. It is the quantity contained in the ratio.

  If the added amount of the cationic starch is less than 0.2% by mass, sufficient paper strength cannot be obtained, and this causes the generation of paper dust. If the added amount exceeds 2.0% by mass, the paper becomes hard and loses its flexibility and is easily broken. . On the other hand, if the addition amount of the anti-slip agent is less than 0.2% by mass, the paper becomes slippery. Even if the addition amount exceeds 2.0% by mass, no further effect is obtained and the cost is increased. Further, if the addition amount of the release agent is less than 0.1% by mass, there is a problem that the papermaking sticks to the dryer during papermaking. If the addition amount exceeds 0.4% by mass, slipping tends to occur during winding.

  In the present invention, the anti-slip agent is a cationic styrene resin, alkyl ketene dimer, alkenyl succinic anhydride, isocyanate aziridine derivative, succinimide derivative, carbonyl derivative, rosin anhydride, fatty acid anhydride, resin-type cation sizing agent It is an additive that suppresses slipping of paper, such as a polymer-type cation sizing agent. Of these, cationic styrene resins are particularly preferred because they are excellent in the anti-slip effect in the present invention.

  In the present invention, the release agent is a modified hydrocarbon oil, silicone oil, silicone resin, fluororesin, mineral oil or the like. Among these, the modified hydrocarbon oil is particularly preferable because it is excellent in the effect of preventing the papermaking from sticking to a heating drum such as a dryer during papermaking.

  Among the additives in the present invention, the cationic starch and the anti-slip agent are used in the interleaving paper in addition to the effect for stably making the above interleaving paper and the effect of improving the surface characteristics of the obtained interleaving paper. This suppresses the generation of sulfate ions or chlorine ions at the surface, and as a result, suppresses discoloration and alteration of the metal portion. Further, among the additives in the present invention, the release agent has an effect for stably making the above slip paper.

  The content ratio of chlorine contained in the neutral metal interleaving paper of the present invention is preferably 200 ppm or less in terms of chlorine ion concentration. If this chlorine ion concentration exceeds 200 ppm, when the slip sheet is used as a process slip sheet and / or product slip sheet for an electronic component lead frame, the metal portion of the lead frame, particularly copper or silver, will be corroded. May be altered.

  In the present invention, the neutral paper means one having a pH of 6 to 8 in the paper surface.

[Method for producing neutral metal interleaving paper]
In the neutral metal interleaving paper of the present invention, the raw material pulp is beaten so that the drainage degree of the raw material pulp is in the range of 300 to 550 cm ³ . 2 to 2.0% by mass, an anti-slip agent is added in an amount of 0.2 to 2.0% by mass and a release agent is contained in a proportion of 0.1 to 0.4% by mass, and aluminum sulfate is not added. It can be produced by making paper while keeping the pH of the aqueous slurry of raw pulp in the range of 7-8.

In the manufacturing method of the neutral metal interleaving paper of this invention, it has at least a raw material process, a papermaking process, a drying process, and a calendar process as a manufacturing process. First, in the raw material process, the raw material pulp is beaten so that the freeness of the raw material pulp is in the range of 300 to 550 cm ³ . Subsequently, an additive consisting of a cationic starch, an anti-slip agent and a release agent was added to the interleaf paper in which the cationic starch was 0.2 to 2.0% by mass, the anti-slip agent was 0.2 to 2.0% by mass and the release agent was 0. 0.1 to 0.4% by mass is added so that it is contained. By making the freeness of the raw pulp within the above range, it is possible to make a slip sheet stably. Moreover, quality, such as surface smoothness, of the obtained slip paper can be made uniform.

  In the present invention, aluminum sulfate (sulfuric acid band) is not added, but due to the mixing of sulfuric acid band contained in the raw material pulp or sulfuric acid band remaining in the papermaking equipment, If aluminum sulfate is a trace amount of 200 ppm or less, it may be contained.

  Furthermore, the pH of the water slurry of raw material pulp is adjusted to be in the range of 7-8. The pH is adjusted, for example, by adding an aqueous solution of sodium hydroxide, potassium hydroxide or the like or an aqueous solution of organic acid such as citric acid to a raw material pulp tank or the like. For the pH adjustment, metal corrosive inorganic acids such as sulfuric acid and hydrochloric acid are not used.

  The water slurry of the raw pulp whose freeness and pH are adjusted in the paper making process is made with a paper machine equipped with, for example, a wire mesh and a felt endless belt to obtain wet paper.

  Next, in the drying step, the surface of the wet paper is brought into contact with the surface of the heating drum of the dryer and dried to obtain a dry paper. Furthermore, the neutral metal interleaving paper of the present invention is manufactured by calendering the surface of the dry interleaving paper in the calendering process.

  In the production of the neutral metal interleaving paper of the present invention, deinked pulp or bleached wood pulp obtained by deinking mainly used paper such as imitation waste paper, newspaper waste paper, and magazine waste paper can be used as the raw material pulp for the surface layer. As a raw material for the middle layer and the back layer in the case of multilayer paper, recovered pulp such as used newspaper, magazine used paper, used corrugated cardboard, old paper used paper, miscellaneous used paper, or wood pulp such as kraft pulp can be used.

  In the present invention, as the raw material pulp used for the papermaking of the neutral metal interleaving paper, the above-mentioned pulp can be used. It is preferable to use those containing 200 ppm or less. When a pulp having an aluminum sulfate content exceeding 200 ppm is used as a raw material pulp, it is preferably used by mixing with a pulp having a low aluminum sulfate content. Or it is preferable to use the pulp which isolate | separated water, after extracting aluminum sulfate with water in a raw material process.

  The obtained neutral metal interleaving paper can be made into a roll-up product in a roll shape by a take-up reel.

[Substrate having metal surface or metal plating surface]
The neutral metal slip sheet of the present invention is a base material slip sheet having a metal surface or a metal plating surface. Examples of the base material having the metal surface or the metal plating surface include a lead frame and a shadow mask of a base material for an electronic component.

  EXAMPLES Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto. In addition, each evaluation characteristic in an Example was measured with the following method.

[Aluminum sulfate concentration]
The aluminum sulfate concentration in the slip sheet was measured by the following test method.
(1) A test piece is cut into 10 mm squares or less and 40 g is prepared in the atmosphere that matches the conditions of JIS P8111.
(2) After passing distilled water through an ion exchange resin for pure water, it is boiled for 5 to 6 minutes to obtain pure water.
(3) In an Erlenmeyer flask with an air cooling tube, add 40 g of the test piece of (1) and 350 cm ³ of pure water of (2), heat at 100 ° C. for 1 hour in a thermostatic bath, and then at 23 ° C. ± 5 ° C. Cool and filter through a glass filter.
(4) Take 200 cm ³ of the filtrate in a beaker, add 2 cm ³ of hydrochloric acid and heat until boiling.
(5) Take 50 cm ^{3 of} the samples prepared in (4) in two 100 cm ³ beakers.
(6) was added respectively and glycerol solutions 10 cm ³ and sodium chloride solution 5 cm ³ in both beakers, stir well and agitator. (Glycerin solution is obtained by mixing the glycerine and pure water at 1 part by weight to 1 part by weight. Sodium chloride solution was in 1000 cm ³ Pure water was added to the NaCl40g and HCl20cm ^3, and filtered through a 5C filter paper )
(7) Add 0.3 g of barium chloride to one beaker, stir for 1 minute, let stand for 4 minutes, and stir again for 15 seconds.
(8) A part of the solution obtained by adding barium chloride to the absorption cell is taken, and the absorbance at a wavelength of about 420 nm is measured using a solution not containing barium chloride as a control.
(9) From the calibration curve, obtain the amount of sulfate ion (mgSO ₄ ²⁻ ) and convert it to the amount of aluminum sulfate. (A calibration curve is prepared in advance by measuring the absorbance around a wavelength of 420 nm of a solution having a known sulfate ion concentration.)
[Chlorine ion concentration]
The chlorine ion concentration in the slip paper was measured by the following test method.
(1) A test piece is cut into 10 mm squares or less and 10 g is prepared in the atmosphere that matches the conditions of JIS P8111.
(2) After passing distilled water through an ion exchange resin for pure water, it is boiled for 5 to 6 minutes to obtain pure water.
(3) In an Erlenmeyer flask with an air cooling tube, add 10 g of the test piece of (1) and 180 cm ³ of pure water of (2), heat at 100 ° C. for 1 hour in a thermostatic bath, and then increase to 23 ° C. ± 5 ° C. Cool and filter through filter paper (2C).
(4) Dispense 50 cm ³ of the filtrate into a colorimetric tube. As a blank test, 50 cm ^{3 of} pure water is also prepared.
(5) Add 10 cm ^{3 of} ammonium iron sulfate solution and 5 cm ³ of mercuric ethanol thiocyanate to each sample, cap, shake well and leave for 10 minutes.
(6) Each solution prepared in (5) is transferred to an absorption cell, and the absorbance at a wavelength of 473 nm is measured using a blank test solution as a control.
(7) The amount of chloride ion (mgCl ⁻ ) is determined from the calibration curve. (A calibration curve is prepared in advance by measuring the absorbance at a wavelength of 473 nm of a solution having a known chloride ion concentration.)
[Metal surface alteration]
Ply paper and copper circuit and lead frame of electronic parts with silver-plated circuit part are alternately stacked 50 layers, accelerated test (100 ° C, 60 minutes), copper circuit and silver-plated circuit part are observed, and the following standards Evaluated.
○: No discoloration is observed in the copper circuit and silver-plated circuit parts.
Δ: Some discoloration in the copper circuit and silver-plated circuit parts.
X: Discoloration is remarkably recognized in the copper circuit and silver plating circuit portions.

[Formability of interleaving paper]
When the interleaf paper was continuously produced for 24 hours, the paper breakage in the paper making process and the surface fluffing state were confirmed and evaluated according to the following criteria.
○: Paper breakage and surface fuzz are not recognized.
X: Paper breakage occurred once or more, or surface fluffing was observed.

[Winding finish of interleaving paper]
When the interleaf paper was continuously finished with a small roll of 10,000 m, the deformation of the take-up (paper tube misalignment) and the paper dust adhering to the paper roll of the finishing machine were confirmed and evaluated according to the following criteria.
○: Paper tube misalignment of winding and paper dust adhesion to finishing machine are not recognized.
X: Paper tube misalignment of winding is recognized. Or paper dust adheres to the finishing machine.

[Example 1]
Using LBKP as a raw material pulp, it was beaten so as to have a freeness of 400 cm ³ , thereby preparing an aqueous slurry of the raw material pulp (pulp concentration: 3% by mass). In this water slurry, 1.0% by mass of cationic starch, 0.2% by mass of cationic styrene resin as an anti-slip agent, and 0.1% by mass of modified hydrocarbon oil as a release agent were added, and sulfuric acid was added. Without adding aluminum, the pH of the water slurry of the raw pulp was adjusted to 7.5 and supplied to a Yankee paper machine, and paper was made to produce a neutral metal interleaving paper. Table 1 shows the evaluation results of this slip sheet.

[Examples 2-3 and Comparative Examples 1-3]
A neutral metal interleaving paper was produced in the same manner as in Example 1 except that the compounding amounts of the cationic starch, the anti-slip agent and the release agent were changed as shown in Table 1. Table 1 shows the evaluation results of the obtained slip sheet.

In addition, the additives in Table 1 are as follows.
Cationic starch: Nippon NSC Co., Ltd., product number Kate 304
Anti-slip agent: manufactured by Arakawa Chemical Industries, Ltd., product number NA size release agent: manufactured by Seiko PMC Co., Ltd., product number CA-900 (modified hydrocarbon oil)
As is clear from the results shown in Table 1, the neutral metal interleaving papers of the examples have excellent papermaking properties and winding finish properties, have no discoloration of the metal surface, and are excellent as neutral metal interleaving papers. It was.

Claims (4)

In the neutral metal interleaving paper used for the metal interleaving paper, in the neutral metal interleaving paper, the cationic starch is 0.2 to 2.0 mass%, the anti-slip agent is 0.2 to 2.0 mass%, and A neutral metal interleaving paper characterized in that a release agent is contained at a ratio of 0.1 to 0.4% by mass, and aluminum sulfate contained in the neutral metal interleaving paper is 200 ppm or less. The neutral metal interleaving paper according to claim 1, wherein a content ratio of chlorine contained in the neutral metal interleaving paper is 200 ppm or less in terms of chlorine ion concentration. The neutral metal interleaving paper according to claim 1 or 2, which is used for process interleaving paper or product interleaving paper for electronic component lead frames. A method for producing a neutral metal interleaving paper in which the aluminum sulfate in the interleaving paper is 200 ppm or less in terms of sulfate ion concentration, and the raw pulp is beaten so that the freeness of the raw pulp is in the range of 300 to 550 cm ³ . In addition, in the water slurry of the raw material pulp, the cation starch is 0.2 to 2.0 mass%, the anti-slip agent is 0.2 to 2.0 mass%, and the release agent is 0.1 to 0.4 mass% in the interleaving paper. A neutral metal interleaving paper characterized in that it is added so as to be contained at a ratio of%, aluminum sulfate is not added, and papermaking is carried out while maintaining the pH of the raw pulp water slurry in the range of 7-8.