JP5470980B2 - Manufacturing method of multilayer paper base material for chip type electronic component storage mount - Google Patents

Description

  The present invention relates to a multilayer paper base material for manufacturing a paper-made chip-type electronic component storage board for storing chip-type electronic components, and a method for manufacturing the same.

A chip-type electronic component storage mount (hereinafter abbreviated as “storage mount”) used as a carrier for chip-type electronic components is usually formed in a tape shape and embossed or perforated to form a cavity. It is manufactured by doing.
The storage board is used as follows.
That is, in the case of a storage board obtained by embossing a paper base material, the chip-type electronic component is filled in the cavity as it is, and in the case of a storage board obtained by punching, the bottom cover tape is bonded to the back surface (bottom side). After providing the bottom surface, the chip-type electronic component is filled into the cavity.
Thereafter, the top cover tape is bonded to the front surface (top side) and wound around a cassette reel before shipment. Then, the user peels off the top cover tape, takes out the chip-type electronic component filled in the cavity, and mounts it on the printed board.

  Since it is used as described above, the storage board must not have an adverse effect on the quality of the filled chip-type electronic components, the surface must be smooth so that the cover tape can be satisfactorily adhered, and the cassette reel It has strength that does not cause delamination or cracking of the mount due to bending stress such as winding around it, the accuracy of forming the cavity for inserting the chip-type electronic component is good, the filling and taking out of the electronic component is smooth, the cavity There is a demand for less wear on the mold used for forming.

Among these, it is particularly important that the cavity formation accuracy is good. That is, in the cavity formation using the punching machine or the embossing machine, if the inner wall surface of the cavity is not formed sharply (accurate dimension), the chip-type electronic component is easily caught. Therefore, trouble may occur when the chip type electronic component is filled by the chip manufacturer or when the chip type electronic component is taken out by the mounting manufacturer.
In order to improve the cavity formation accuracy, it is possible to take measures such as refinishing or renewing the mold, but the loss of time and yield occurs and the operability is reduced, resulting in higher costs. .

In addition, in order to improve the formation accuracy of the cavity, a method for improving the wear of the mold by improving the mold itself has been carried out, but improvement on the side of the storage board that stores the chip-type electronic components is also required. It has been.
For example, Patent Documents 1 and 2 disclose a method for improving the formability of the cavity by adjusting the density of the paper on the storage board.
Patent Document 3 discloses a method of adjusting the cavity forming property by adjusting the breaking elongation in the vertical direction and the horizontal direction of the paper in the storage board.
Patent Document 4 describes a method for improving the cavity forming property by adjusting the ash content of the storage board.
However, the chip-type electronic components housed in the cavities are becoming more and more compact, and even with the methods described in Patent Documents 1 to 4, the actual situation is that the formation accuracy of the cavities is not sufficient. In addition, the methods described in Patent Documents 1 to 4 have not sufficiently solved the occurrence of delamination due to bending stress and the generation of paper dust when forming cavities.

JP 2000-43975 A JP 2002-53195 A JP 2003-95320 A JP 2006-143227 A

  It is an object of the present invention to prevent mold wear when forming a cavity for housing a chip-type electronic component by punching or embossing and improve the formation accuracy of the cavity, and delamination due to bending stress Another object of the present invention is to provide a multilayer paper base material for storage board that can prevent the generation of paper dust when forming a cavity, and a method for manufacturing the same.

  The present inventors examined raw materials used for a multilayer paper base material for storage board, in particular, pulp fibers and inorganic fillers. As a result, it was found that the problems of the present invention can be solved by using pulp fibers derived from waste paper and inorganic fillers derived from waste paper, and further specifying the content of pulp fibers and inorganic fillers and the particle diameter of the inorganic filler. It was. And based on the knowledge, it further examined and invented the following multilayer paper base materials for storage board and its manufacturing method.

That is, the present invention includes the following inventions.
[1] A used paper pulp manufacturing process for manufacturing used paper pulp containing pulp fibers and inorganic fillers from used paper, and a paper making process for making a multilayer paper base material using fresh pulp and used paper pulp,
In the waste paper pulp manufacturing process, waste paper containing 5% by mass or more of inorganic filler as ash is disaggregated and dust-removed, and then the weight average particle diameter of the inorganic filler is less than 50 μm, and the particle diameter occupied by the inorganic filler Dispersing using a hot disperser so that the content of inorganic filler of 50 μm or more is less than 40% by mass,
In the papermaking process, the waste paper pulp is used for papermaking of layers other than the surface layer, and the total pulp fiber contained in the layer other than the surface layer is a fiber length distribution in which the proportion of fine fibers having a length of 0.2 mm or less is 20 to 70%. A method for producing a multilayer paper base material for chip-type electronic component storage board, wherein waste paper pulp is blended so as to have
However, the fiber length distribution is the fiber length of the measurement sample disaggregated by the pulp disaggregation method of JIS P8220. Has been measured by the pulp fiber length testing method in an optical automatic measurement method defined in 52, Ru fiber length distribution der determined by numbers.

According to the multilayer paper base material of the present invention, it is possible to prevent mold wear when forming a cavity for housing a chip-type electronic component by punching or embossing, and improve the formation accuracy of the cavity. Moreover, according to the multilayer paper base material of the present invention, it is possible to prevent delamination due to bending stress and generation of paper dust when forming a cavity.
According to the method for producing a multilayer paper substrate of the present invention, the multilayer paper substrate as described above can be easily produced.

It is sectional drawing which shows one Embodiment of the multilayer paper base material for storage mounts of this invention. It is an example of the photograph of the cavity image | photographed when evaluating cavity formation precision. FIG. 3 is a schematic diagram of the photograph of FIG. 2.

(Multilayer paper base material for chip-type electronic component storage mount)
An embodiment of a multilayer paper substrate for chip-type electronic component storage board of the present invention (hereinafter abbreviated as “multilayer paper substrate”) will be described.
The multilayer paper base material of the present embodiment is a multilayer paper base material made using fresh pulp and waste paper pulp as a papermaking raw material, and has a surface layer 10, an intermediate layer 21, and a back layer 22, as shown in FIG. It consists of a back layer 20. Here, the surface layer 10 is an outer layer on the side to which the top cover tape is bonded, and the back layer 22 is an outer layer on the side opposite to the side to which the top cover tape is bonded. Moreover, it is preferable that the middle layer 21 in the middle back layer 20 is a multilayer. One surface layer 10 and one back layer 22 are sufficient.

[Fresh pulp]
In the present invention, fresh pulp is pulp obtained from wood or non-wood plants. Fresh pulp made from plants does not contain inorganic fillers.
Examples of the fresh pulp include bleached chemical pulp (NBKP, LBKP, etc.), unbleached chemical pulp (NUKP, LUKP, etc.), mechanical pulp, non-wood fiber pulp, and the like. Of these, bleached chemical pulp is more preferred because it easily develops strength and is difficult to be colored.

[Waste paper pulp]
In the present invention, the used paper pulp is a pulp obtained by recycling used paper.
Here, as used paper, for example, white paper, ruled white, etc., once used, but paper with few printed parts, printed matter such as cards, imitations, colored, Kent, white art, etc. and colored and used once Used high-quality used paper such as paper, coated paper for printing, beverage packs, office paper, and other business-grade used paper such as special cutting, separate upper cutting, medium-quality anti-old, Kent Manila, newspapers, magazines, miscellaneous Examples include general medium-sized waste paper such as paper, and tea-based waste paper such as cut tea, plain tea, miscellaneous bags, and cardboard.
Among these, since the ink content derived from the waste paper in the multilayer paper base material is reduced, paper having few printed portions is preferable.

  The waste paper pulp is preferably uncolored, such as disintegrated pulp of waste paper that has not been printed, or deinked waste paper pulp that has been deinked to remove ink. If the inside of the cavity for storing the electronic component is colored, there is a possibility that it is erroneously identified as the component in the image processing in the inspection process after storing the component or after removing the component.

  Waste paper pulp made from waste paper usually contains an inorganic filler. Here, the inorganic filler is derived from the filler internally added to the waste paper and the pigment in the coating layer.

[Surface]
Usually, in the storage board, after the chip-type electronic component is stored in the cavity, the top cover tape is bonded, and the top cover tape is peeled off by the end user, and the chip-type electronic component is taken out. Therefore, since the surface layer 10 of the multilayer paper substrate 1 for storage board is required to have high adhesiveness to the top cover tape and appropriate peelability, it is preferable to use only fresh pulp containing no inorganic filler. .
A fresh pulp suitable for the surface layer 10 includes, but is not limited to, bleached chemical pulp.

  The Canadian standard freeness of the entire pulp fiber constituting the surface layer 10 is preferably 300 to 560 ml, and more preferably 300 to 500 ml. If the Canadian standard freeness of the pulp fiber as a whole is 300 ml or more, it is possible to prevent a decrease in the pulp yield and a quantity loss due to high density, and if it is 560 ml or less, the interlayer strength can be further increased.

In order to prevent the peelability of the top cover tape and generation of cracks, the surface layer 10 may contain an internal additive for other purposes.
Examples of the internal additive include natural and synthetic rosin-based sizing agents, styrene / maleic acid copolymer resins, styrene / acrylic copolymer resins, styrene / olefin acid copolymer resins, alkyl ketene dimers, alkenyl succinic anhydrides, and the like. Examples thereof include an internal sizing agent for papermaking, a paper strength enhancer, a drainage yield improver, a water-resistant agent, and an antifoaming agent.
Further, cationic polymers such as cationized starch, cationized polyacrylamide, polyethyleneimine, polyamide polyamine epichlorohydrin, cation-modified guar gum, and cation-modified polyvinyl alcohol may be contained.

In view of further preventing delamination, it is preferable to contain an amphoteric polyacrylamide paper strength enhancer having a molecular weight of 2 million or more. The amphoteric polyacrylamide paper strength enhancer can adsorb to the pulp fiber through aluminum in the anion part, and can self-adsorb in the cation part, is hardly affected by pH change caused by waste paper and / or filler, and stably between fibers. Can strengthen the bond. If the molecular weight of the amphoteric polyacrylamide paper strength enhancer is 2 million or more, delamination can be sufficiently prevented.
The content of the amphoteric polyacrylamide paper strength enhancer is preferably 0.5 to 5.0% by mass when the pulp fiber is 100% by mass. When the amount of the amphoteric polyacrylamide paper strength enhancer added is 0.5% by mass or more, the paper strength enhancing effect can be sufficiently exhibited. However, adding more than 5.0% by mass only increases the cost because the paper strength enhancing effect reaches its peak.

[Inner layer]
Each layer constituting the inner back layer 20 may be one in which all layers are made using the same papermaking raw material, or may be made using different papermaking raw materials. As will be described later, since the middle layer 21 and the back layer 22 have different preferable configurations, it is preferable that the middle layer 21 and the back layer 22 are made by using different papermaking raw materials.

The pulp in the papermaking raw material of the inner back layer 20 includes waste paper pulp. By including waste paper pulp as a raw material for the inner back layer 20, the multilayer paper substrate 1 as a whole satisfies the following conditions.
The total content of the used paper pulp fiber and the inorganic filler in the multilayer paper base material 1 determined by the following formula is 5 to 70% by mass. The total content of the used paper pulp fiber and the inorganic filler is preferably 10 to 50% by mass.
α ₁ = (M ₁ / N ₁ ) × 100 (%)
Here, α ₁ is the total content of the used paper pulp fiber and the inorganic filler in the multilayer paper base material 1, M ₁ is the total mass of the used paper pulp fiber and the inorganic filler in the inner back layer 20, and N ₁ is the multilayer. It is the dry solid content mass of the paper substrate 1.
When the total content of the waste paper pulp fiber and the inorganic filler in the multilayer paper base material 1 is less than 5% by mass, the cavity formation accuracy is lowered, and when it exceeds 70% by mass, the fiber-to-fiber bond becomes too weak. There is a possibility of delamination and paper dust is likely to be generated.
The total content of the used paper pulp fiber and the inorganic filler in the multilayer paper substrate 1 increases as the blending ratio of the used paper pulp forming the inner back layer 20 increases, and the inner back layer 20 in the multilayer paper substrate 1 increases. The higher the mass ratio, the greater.

The ash content is 1 to 15% by mass, and preferably 1 to 10% by mass. Here, the ash content is a value obtained by calcining a sample of the multilayer paper base material 1 at 525 ° C. according to JIS P 8251 and using the following formula.
β ₁ = (P ₁ / Q ₁ ) × 100 (%)
Here, β ₁ is ash, P ₁ is the mass of the residue after firing, and Q ₁ is the dry solid content of the multilayer paper substrate 1 before firing.
When the ash content is less than 1% by mass, the mold cannot be prevented from being worn. When the ash content exceeds 15% by mass, the interlaminar strength is reduced or paper dust tends to be generated. The ash content corresponds to the amount of inorganic filler.
Since the ash content is derived from waste paper pulp, the ash content is adjusted by the proportion of the used paper pulp and the proportion of the inorganic filler contained in the used paper to obtain the used paper pulp.

The mass average particle diameter of the inorganic filler is less than 50 μm, preferably less than 40 μm. When the inorganic filler has a mass average particle size of less than 50 μm, the inorganic filler can easily move when the mold for forming the cavity comes into contact with the inorganic filler, so that wear of the mold can be prevented.
The content of the inorganic filler having a particle size of 50 μm or more in the inorganic filler is less than 40% by mass, preferably less than 30% by mass, and most preferably 0% by mass with respect to 100% by mass of the total inorganic filler. An inorganic filler having a particle diameter of 50 μm or more has a high probability of coming into contact with a mold when forming a cavity for housing a chip-type electronic component. Therefore, when a large inorganic filler having a particle size of 50 μm or more is contained in an amount of 40% by mass or more, the mold is easily worn.

  In order to make the particle size distribution of the inorganic filler within the above-described range, the treatment conditions (for example, dispersion time, shear efficiency, treatment temperature, etc.) of the dispersion treatment described later may be appropriately adjusted. For example, the longer the dispersion time and the higher the shear efficiency, the smaller the mass average particle size and the smaller the content of inorganic fillers with a particle size of 50 μm or more.

The particle diameter in the present invention is the longest length of each inorganic filler in an image obtained by photographing a cross section with an electron microscope. For example, when the inorganic filler looks like a rod, it is the length, and when it looks like an ellipse, it is the major axis.
The content of the inorganic filler having a mass average particle diameter and a particle diameter of 50 μm or more is determined as follows.
First, as in the example shown in Table 1, inorganic fillers having a particle diameter of 5 μm or more and less than 250 μm are classified into any one of sections i every particle diameter of 10 μm (A). B _i is an intermediate particle size between the upper limit particle size and the lower limit particle size in section i. Further, the ratio of the number of inorganic fillers included in the particle diameter range of the section i to the total number of inorganic fillers having a particle diameter of 5 μm or more and less than 250 μm is a number ratio C _i . Here, the total number of inorganic fillers having a particle diameter of 5 μm or more and 250 μm was set to 100 mass% because inorganic fillers having a particle diameter of less than 5 μm do not affect the wear of the mold. When an inorganic filler having a particle diameter of 250 μm or more is present, the calculation is performed by increasing the section i so that the filler having the maximum diameter is included.
Then, the mass ratio _{D i} of the interval i is obtained by Equation 1. Then, the mass average particle diameter is obtained by [Equation 2]. The content of the inorganic filler having a particle diameter of 50 μm or more is obtained by [Equation 3].

Note that in [Expression 1], to use a square value of B _i is waste paper from the inorganic filler, in particular, inorganic fillers from the coating layer of the coated paper, it has become thin tabular This is because there are many.
Further, in the present invention, it is inappropriate to define the average particle size of the inorganic filler on the basis of a number for the following reason. That is, even if the proportion of the number of inorganic fillers having a small particle size is large, the presence of a small number of large inorganic fillers having a particle size exceeding 100 μm increases the probability that the mold will cut large particles, Mold wear is likely to occur.

It is preferable that all pulp fibers contained in the inner back layer 20 have a fiber length distribution in which the proportion of ultrafine fibers having a length of 0.2 mm or less is 20% or more. The fiber length distribution in the present invention is the fiber length of the measurement sample disaggregated by the pulp disaggregation method of JIS P8220. 52 is a fiber length distribution measured by a pulp fiber length test method using an optical automatic measurement method defined in 52 and obtained on the basis of a number.
When the ratio of the ultrafine fibers having a length of 0.2 mm or less is 20% or more, the bonding force between the fibers having a length exceeding 0.2 mm can be increased, and the cavity forming property is further improved.
Moreover, it is preferable that the ratio of the ultrafine fiber of 0.2 mm or less is 70% or less. If the ratio of the ultrafine fibers is 70% or less, paper drainage is easily made because the drainage of the pulp fibers is hardly inhibited.
In order to adjust the proportion of ultrafine fibers having a length of 0.2 mm or less, the proportion of waste paper pulp forming the inner back layer 20 may be adjusted. Specifically, the proportion of fibers having a length of 0.2 mm or less increases as the proportion of used paper pulp increases. In addition, after obtaining waste paper pulp from waste paper, it may be adjusted by performing a beating process described later.

  The Canadian standard freeness of the whole pulp fibers constituting the inner backing layer 20 is preferably 250 to 500 ml, and more preferably 250 to 450 ml.

<Back layer>
The back layer 22 preferably has a small content of inorganic filler, and more preferably contains no inorganic filler. However, the same papermaking material as that for the middle layer 21 may be used as the papermaking material for the back layer 22.
In order to reduce the content of the inorganic filler, the back layer 22 preferably has a low content of used paper pulp, and more preferably does not contain any used paper pulp.
If the content of the inorganic filler in the back layer 22 is small, the surface smoothness of the back layer 22 can be increased. Since a bottom cover tape may be bonded to the back layer 22, higher surface smoothness is preferable in terms of adhesiveness.

<Middle layer>
The middle layer 21 preferably satisfies the following conditions as a whole. If the following conditions are satisfied, each condition of the inner back layer 20 described above can be easily satisfied.
The total content of the used paper pulp fiber and the inorganic filler in the middle layer 21 determined by the following formula is preferably 5 to 80% by mass, and more preferably 10 to 60% by mass.
α ₂ = (M ₂ / N ₂ ) × 100 (%)
Here, α ₂ is the total content of the paper pulp fiber and the inorganic filler in the middle layer 21, M ₂ is the total mass of the waste paper pulp fiber and the inorganic filler in the middle layer 21, and N ₂ is the dry solid mass of the middle layer 21. It is.
The total content of the used paper pulp fiber and the inorganic filler in the middle layer 21 increases as the blending ratio of the used paper pulp forming the middle layer 21 increases.

The middle layer 21 preferably has an ash content of 2.0 to 20% by mass. Here, the ash content of the middle layer 21 is a value obtained by the following equation after collecting the middle layer 21 as a sample according to JIS P 8251 and firing at 525 ° C.
β ₂ = (P ₂ / Q ₂ ) × 100 (%)
Here, β ₂ is the ash content of the middle layer 21, P ₂ is the mass of the residue after firing, and Q ₂ is the dry solid content mass of the middle layer 21 before firing.
The ash content of the middle layer 21 is adjusted by the blending ratio of the used paper pulp of the middle layer 21 and the ratio of the inorganic filler contained in the used paper to obtain the used paper pulp.

The total pulp fibers contained in the middle layer 21 preferably have a fiber length distribution in which the ratio of ultrafine fibers having a length of 0.2 mm or less is 20% or more, and the fiber length distribution in which the ratio of ultrafine fibers is 25 to 50%. It is more preferable to have.
In order to adjust the ratio of ultrafine fibers having a length of 0.2 mm or less contained in the middle layer 21, the blending ratio of waste paper pulp forming the middle layer 21 may be adjusted. Specifically, the proportion of fibers having a length of 0.2 mm or less increases as the proportion of used paper pulp increases.

[Function and effect]
Many fresh pulp fibers are relatively hard, have a long fiber length, and have a cross section close to a perfect circle. On the other hand, in the waste paper pulp fiber recycled from waste paper through the steps (history) of disaggregation, beating, drying, and papermaking for pulping and papermaking, the fibers are treated by chemical treatment and mechanical treatment during the regeneration step. It is getting shorter. That is, waste paper pulp fiber contains many short fibers. Short fibers serve to reinforce fiber intersections with thick fiber networks such as fresh pulp fibers. Therefore, in the multilayer paper base material of the present invention including waste paper pulp fibers, it is possible to prevent the thick fibers from being separated when the mold comes into contact with the cavity during formation.
Moreover, the inorganic filler derived from waste paper can inhibit the bonding between fibers and reduce the bonding force between fibers. Therefore, the stress on the mold during punching or embossing when forming the cavity is reduced, and wear is prevented. However, the inorganic filler having a large particle size is rather stress on the mold. Therefore, in the present invention, by specifying the mass average particle size and particle size distribution of the inorganic filler, stress on the mold is reliably reduced and wear is prevented.
Thus, in the multilayer paper base material of the present invention, thick fibers remain bonded even at the time of forming the cavity, and wear of the mold is prevented. Therefore, the cavity inner wall surface is sharp and the cavity formation accuracy is high.
Furthermore, since the bonds between the fibers are strong, delamination due to bending stress is prevented.

(Manufacturing method of multilayer paper substrate)
The method for producing a multilayer paper base material of the present invention includes a waste paper pulp production process for producing waste paper pulp containing pulp fibers and an inorganic filler from waste paper, and papermaking for making a multilayer paper base material using fresh pulp and waste paper pulp. Process.

[Paper pulp manufacturing process]
In the used paper pulp manufacturing process, the used paper is disaggregated and subjected to a dust removing process, followed by a dispersing process.
Here, as the used paper, since the inorganic filler in the used paper can be effectively used, a paper containing 5% by mass or more, preferably 7% by mass or more of the inorganic filler is used. Moreover, it is preferable that the inorganic filler in a used paper is 40 mass% or less in the point of utilizing a used paper pulp fiber effectively.

The disaggregation process is a process of disaggregating waste paper to form a slurry, and a disaggregator called a pulper is usually used.
Examples of the pulper include a low-concentration pulper that is treated at 3 to 5% by mass, a medium-concentration pulper that is treated at 5 to 18% by mass, and a high-concentration pulper that is treated at 18 to 25% by mass.
Examples of the low-concentration pulper include those in which a stirring blade called a rotor is attached to the bottom surface or inner wall surface of a tank. The medium concentration pulper is the same as the above low concentration pulper, and includes a rotor with a larger rotor shape and a disaggregation tank with a horizontal drum shape. An example of the high-concentration pulper is a kneading pulper in which stirring blades are installed in multiple stages in the tank.
In addition, when used paper is difficult to disaggregate, a defibrating machine can be used in addition to the disaggregating machine.

The dust removal treatment is a treatment for removing foreign matters other than pulp fibers and inorganic fillers, and a cleaner and a screen capable of removing foreign matters are used.
The cleaner has a conical shape and removes foreign matters having a specific gravity larger than that of pulp fibers such as sand and metal particles by the principle of centrifugal separation.
As the screen, for example, a basket type screen in which holes and slits having a predetermined opening area are formed is used. In order to improve the processing efficiency, it is preferable to rotate or vibrate the basket or rotate the rotor.
Further, as the screen, a Jansson screen for removing a large foreign matter or a flat flat screen can be used.

In the dispersion treatment, the inorganic filler is dispersed so that the mass average particle diameter of the inorganic filler is less than 50 μm, and the content of the inorganic filler having a particle diameter of 50 μm or more in the inorganic filler is less than 40 mass%. In this dispersion treatment, not only the inorganic filler but also the remaining ink can be reduced.
When used magazine waste paper containing a large amount of coated paper having a coating layer containing a pigment and not sufficiently dispersed by the disaggregation treatment (particularly when the coating layer is thick), the inorganic filler is a relatively large lump. May remain. This lump is not removed by dust removal and may be contained in waste paper pulp. When a multilayer paper base material obtained using waste paper pulp containing a large inorganic filler is subjected to punching or embossing, there is a risk that the wear of the mold is accelerated. However, even if used paper containing a large amount of coated paper is used, the content of the inorganic filler having a mass average particle diameter of the inorganic filler of less than 50 μm and a particle diameter of 50 μm or more in the inorganic filler in the dispersion treatment If the inorganic filler is dispersed so that is less than 40% by mass, the wear of the mold can be prevented.

Machines that can be used in distributed processing include, for example, disintegrators such as finalers, conifers, top finalers, conical discs, deflakers, conical flakers, power finers, refiners such as refiners, double disc refiners, and beaters, kneaders, dispersers. And kneading / dispersing machine such as New Taizen.
Of these, a disperser or a hot disperser is preferred. When the treatment is performed using a disperser or a hot disperser, the inorganic filler can be made fine with high efficiency without drastically reducing the freeness even if the solid content concentration is 25% by mass or more.
When processing with a disperser or a hot disperser, it is preferable to heat to 80 to 120 ° C. with a steam / heater because the efficiency of the dispersion process is improved.

When the machine used for the dispersion treatment is a disk-type hot disperser in which used paper pulp to be treated passes between two disks, the flexibility increases and the dispersion becomes easy, so It is preferable to heat to ° C.
Further, it is preferable that the gap between the two discs is in an appropriate range. As the gap is smaller, the dispersion efficiency is improved. However, if the gap is excessively reduced, the processing efficiency is lowered and the load tends to be overloaded.

  Through the above-described disaggregation treatment, dust removal treatment and dispersion treatment, the pulp fibers constituting the waste paper are slurried. Further, the filler and pigment in the used paper are refined. For example, one large mass of pigment is broken into tens to hundreds of small particles.

In the case where used printed paper is used, it is preferable to perform deinking processing with a flowator or the like before the dispersion processing.
Since the slurry after the deinking treatment can disperse the ash as well as the remaining ink, it is preferable to perform the dispersion treatment after concentrating until the solid concentration becomes 10 to 35% by mass.

  After the dispersion treatment, it is preferable to further perform a pulp washing treatment. If the pulp washing treatment is performed, the amount of ash in the waste paper can be easily reduced. Specifically, when the pulp washing treatment is performed in combination with the dispersion treatment, the ash content of the used paper pulp is easily reduced to 0.7 to 25% by mass even if a large amount of used paper having an ash content exceeding 25% by mass is used. Can be adjusted. Therefore, in the multilayer paper base material 1 in which the middle back layer 20 is formed using waste paper pulp, the ash content of the middle back layer 20 can be easily adjusted to 2.0 to 20% by mass.

  Examples of machines that can be used in the pulp cleaning treatment include cleaning devices such as DNT washers, compact washers, fall washers, vario splits, SP filters, DP Cosmo, and gap washers.

As the solid content concentration is lower, the ash removal efficiency in the pulp cleaning process is improved. Therefore, it is preferable to dilute the pulp slurry after the dispersion process before the pulp cleaning process.
It is preferable to dilute the pulp slurry after the dispersion treatment before or during the pulp washing step.

[Paper making process]
In the paper making process, waste paper pulp is used for paper making of the inner back layer 20. Only fresh pulp is used for paper making of the surface layer 10. It is preferable to use only fresh pulp for papermaking of the back layer 22, but waste paper pulp can also be mixed and used.
In addition, the papermaking raw material of each layer may contain various internal additives as described above for improving the adhesiveness to the cover tape or for other purposes, if necessary.
The basis weight of the multilayer paper substrate is appropriately selected depending on the size of the chip-type electronic component housed in the cavity, but is usually 200 to 1000 g / m ² .

  As the papermaking method, 3 to 10 layers of multi-layer papermaking is preferable because it is easy to form. Examples of the paper machine used for the multilayer paper making include a circular mesh paper machine, a circular mesh short combination paper machine, a short mesh multilayer paper machine, and a long mesh multilayer paper machine.

A surface treatment agent may be appropriately applied or impregnated on the front surface or the back surface of the multilayer paper substrate 1 in order to improve the adhesiveness with the top cover tape and the bottom cover tape and to prevent the occurrence of blemishes.
Examples of the surface treatment agent include polyvinyl alcohol, starch, polyacrylamide, acrylic resin, styrene / butadiene copolymer resin, styrene / isoprene copolymer resin, polyester resin, ethylene / vinyl acetate copolymer resin, vinyl acetate / vinyl alcohol. Examples thereof include copolymer resins and urethane resins.
Further, styrene / maleic acid copolymer resins and olefin / maleic acid copolymer resins may be used as the surface treatment agent. When a styrene / maleic acid copolymer resin or olefin / maleic acid copolymer resin having a hydrophilic group (carboxy group) is applied, not only the surface coating but also the carboxy group forms a hydrogen bond with the pulp fiber. Can be crosslinked. Therefore, the interfiber bonding can be further improved. By improving the fiber-to-fiber bond, the resistance when peeling the top cover tape or the bottom cover tape is improved, the peel strength can be increased, and the occurrence of cracks can be further prevented.

  Examples of means for applying and impregnating a surface treatment agent on the front or back surface of the multilayer paper substrate 1 include, for example, rolls such as bar coaters, blade coaters, air knife coaters, rod coaters, gate roll coaters, size presses and calendar coaters. A coating device such as a coater or bill blade coater can be used. Among these, a size press or a calendar coater is preferable because the surface treatment agent can be deeply penetrated by the nip pressure.

The coating amount of the surface treatment agent is preferably 0.1 to 1.1 g / m ² in terms of dry coating amount, and more preferably 0.6 to 1.1 g / m ² . If the surface treatment agent is applied so that the dry coating amount is 0.1 g / m ² or more, the generation of scraps and paper dust can be sufficiently suppressed, and the dry coating amount is 1.1 g / m ² or less. As a result, sufficient adhesion to the top cover tape can be secured.

[Function and effect]
In the manufacturing method of the multilayer paper base material 1 mentioned above, the multilayer paper base material 1 is manufactured using the short pulp fiber derived from used paper. In the multilayer paper base material 1 obtained by this manufacturing method, thick pulp fibers can be prevented from being separated from each other at the time of forming a cavity, and the binding force between the fibers is reduced by an inorganic filler derived from waste paper. Therefore, wear of the mold can be prevented and the formation accuracy of the cavity can be increased.
And according to this invention, the inorganic filler (filler, pigment) in waste paper can be utilized effectively.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to the following Example.
In addition, the numerical value which shows a mixing | blending, a density | concentration, etc. is a numerical value of solid content or the mass reference | standard of an active ingredient.

[Manufacture of waste paper pulp]
<Method for producing waste paper pulp A>
The magazine waste paper (ash content 20.3%) is disaggregated with a pulper, passed through a dust remover (cleaner and screen), diluted with water to a solid content concentration of 1%, added with a deinking agent, and deinked with a flowmeter. Was given.
Subsequently, it concentrated to about 30% of solid content concentration with the inclination extractor and the screw press dehydrator.
After that, using a disk-type hot dispersion facility (KRIMA manufactured by Cellwood), a pulp washer (DNT washer was further dispersed while being diluted with water under conditions of a disk gap of 0.2 mm and a temperature of 110 ° C. : Aikawa Tekko Co., Ltd.) to obtain waste paper pulp A containing pulp fibers and inorganic filler. The ash content of this used paper pulp A was measured and found to be 7.3%.

<Method for producing waste paper pulp B>
Kent waste paper (ash content: 33.2%) was disaggregated with a pulper, passed through a dust remover (cleaner and screen), and then concentrated to a solid content concentration of about 30% with a tilt extractor and a screw press dehydrator.
After that, using a disk-type hot dispersion facility (KRIMA manufactured by Cellwood), a pulp washer (DNT washer was further dispersed while being diluted with water under conditions of a disk gap of 0.2 mm and a temperature of 110 ° C. : Manufactured by Aikawa Tekko Co., Ltd.) to obtain waste paper pulp B containing pulp fibers and inorganic filler. The ash content of this used paper pulp B was measured and found to be 23.5%.

<Method for producing waste paper pulp C>
The magazine waste paper (ash content 20.3%) is disaggregated with a pulper, passed through a dust remover (cleaner and screen), diluted with water to a solid content concentration of 1%, added with a deinking agent, and deinked with a floatator. gave.
Then, it concentrated to about 5% of solid content with the inclination extractor.
Thereafter, the paper was passed through a double disc refiner (DDR) twice to reduce the freeness from 358 ml to 187 ml, thereby obtaining waste paper pulp C containing pulp fibers and an inorganic filler. The ash content of this waste paper pulp C was measured and found to be 16.8%.

<Method for producing waste paper pulp D>
Kent waste paper (ash content: 33.2%) is disaggregated with a pulper, passed through a dust remover (cleaner and screen), passed through a double disc refiner at once, the freeness is lowered from 358 ml to 330 ml, and filled with pulp fiber and inorganic matter. Waste paper pulp D containing the material was obtained. The ash content of this waste paper pulp D was measured and found to be 29.1%.

<Manufacturing method of waste paper pulp E>
The magazine waste paper (ash content 20.3%) is disaggregated with a pulper, passed through a dust remover (cleaner and screen), diluted with water to a solid content concentration of 1%, added with deinking agent, and deinked with a floatator. Was given.
Subsequently, it concentrated to about 15% of solid content concentration with the inclination extractor and the screw press dehydrator.
Then, using a disk-type hot dispersion equipment (KRIMA manufactured by Cellwood), a pulp washing machine (DNT washer was added while being dispersed under conditions of a disk gap of 1.0 mm and a temperature of 70 ° C., and further diluted with water. : Manufactured by Aikawa Tekko Co., Ltd.) to obtain waste paper pulp E containing pulp fibers and inorganic fillers. The ash content of this waste paper pulp E was measured and found to be 7.5%.

<Manufacturing method of waste paper pulp F>
Dispose of old magazine paper (ash content: 20.3%) with a pulper, pass through a dust remover (cleaner and screen), dilute with water to a solid content concentration of 1%, add deinking agent, and deinking treatment with a floatator gave.
Subsequently, it concentrated to about 30% of solid content concentration with the inclination extractor and the screw press dehydrator.
After that, it is dispersed by a disperser (TL1 type, manufactured by Aikawa Tekko Co., Ltd.) and further passed through a pulp washing machine (DNT washer: manufactured by Aikawa Tekko Co., Ltd.) while being diluted with water, and used paper pulp F containing pulp fibers and inorganic fillers. Got. The ash content of this waste paper pulp F was measured and found to be 7.3%.

<Method for producing waste paper pulp G>
Dissolve old colored paper (ash content: 31.3%) with a pulper, pass through a dust remover (cleaner and screen), dilute with water to a solid content concentration of 1%, add deinking agent, and deinking with a flow meter Was given.
Subsequently, it concentrated to about 30% of solid content concentration with the inclination extractor and the screw press dehydrator.
After that, it is dispersed with a disperser (TL1 type, manufactured by Aikawa Tekko Co., Ltd.) and further passed through a pulp washing machine (DNT washer: manufactured by Aikawa Tekko Co., Ltd.) while being diluted with water, and used paper pulp G containing pulp fibers and inorganic fillers. Got. The ash content of this waste paper pulp G was measured and found to be 18.8%.

<Method for producing waste paper pulp H>
Disassemble the old magazine paper (ash content 20.3%) with a pulper, pass it through a dust remover (cleaner and screen), dilute with water to a solid content concentration of 1%, add deinking agent, and deink with a floatator Treated.
Then, it concentrated to about 5% of solid content concentration by the inclination extractor.
Thereafter, the double disc refiner was treated in two stages, the freeness was lowered from 358 ml to 232 ml, and used paper pulp H containing pulp fibers and inorganic fillers was obtained. The ash content of this waste paper pulp H was measured and found to be 16.6%.

<Method for producing waste paper pulp I>
Disassemble the old magazine paper (ash content 20.3%) with a pulper, pass it through a dust remover (cleaner and screen), dilute with water to a solid content concentration of 1%, add deinking agent, and deink with a floatator Treated.
Then, it concentrated to about 5% of solid content concentration by the inclination extractor.
Thereafter, the double disc refiner was treated in two stages, the freeness was lowered from 358 ml to 274 ml, and used paper pulp I containing pulp fibers and an inorganic filler was obtained. The ash content of this waste paper pulp I was measured and found to be 16.7%.

<Manufacturing method of waste paper pulp J>
Kent waste paper (ash content: 33.2%) was disaggregated with a pulper and passed through a dust remover (cleaner and screen).
Subsequently, it concentrated to about 30% of solid content concentration with the inclination extractor and the screw press dehydrator.
Then, using a disk-type hot dispersion equipment (KRIMA manufactured by Cellwood), the paper is subjected to dispersion treatment under the conditions of a disk gap of 0.2 mm and a temperature of 110 ° C., and used paper pulp containing pulp fibers and an inorganic filler. J was obtained. The ash content of this waste paper pulp J was measured and found to be 30.3%.

[Manufacture of multilayer paper substrate]
<Example 1>
NBKP; 30% and LBKP; 70% were mixed and beaten with a double disc refiner to prepare 460 ml of CSF (Canadian Standard Freeness) to obtain a surface layer forming pulp slurry.
NBKP; 10%, LBKP; 60%, waste paper pulp A; 30% were mixed and beaten with a double disc refiner to prepare 410 ml of CSF (Canadian Standard Freeness) to obtain a pulp slurry for forming a middle layer.
LBKP was beaten alone with a double disc refiner to prepare 470 ml of CSF (Canadian Standard Freeness) to obtain a pulp slurry for forming the back layer.
A sulfuric acid band was added to each pulp slurry at 2.0% with respect to 100% solid content of the pulp slurry. Moreover, 0.50% of size pine N-111 (manufactured by Arakawa Chemical Industries, Ltd., rosin emulsion sizing agent) was added as a sizing agent to 100% solid content of the pulp slurry. Further, Polystron 1250 (Arakawa Chemical Industries, Ltd., amphoteric polyacrylamide type paper strength enhancer, molecular weight 3 million) was added as a paper strength enhancer by 2.0% with respect to 100% solid content of the pulp slurry.
The above pulp slurry is subjected to multi-layer paper making using a long-mesh five-layer paper making machine so that the surface layer (one layer) is 100 g / m ² , the middle layer (three layers) is 600 g / m ² , and the back layer (one layer) is 100 g / m ^2. Further, 1.0 g / m ² of polyvinyl alcohol having a saponification degree of 88 mol% and a polymerization degree of 1000 as a dry application amount was applied by a size press machine, and then smoothed by a machine calendar to obtain a basis weight of 800 g / m 2. ^2. A multilayer paper substrate having a thickness of 0.95 mm was produced.

<Example 2>
Other than using NBKP: 10%, LBKP: 60%, recycled paper pulp A: 30%, NBKP: 10%, LBKP; 20%, recycled paper pulp B: 70% as raw materials for the middle layer forming pulp slurry Produced a multilayer paper substrate having a basis weight of 800 g / m ² and a thickness of 0.95 mm in the same manner as in Example 1.

<Example 3>
NBKP: 10%, LBKP: 60%, recycled paper pulp A: 30%, NBKP: 10%, LBKP; 40%, recycled paper pulp C: 50%, except for using NBKP; 10%, LBKP; 60%, recycled paper pulp A; 30% Produced a multilayer paper substrate having a basis weight of 800 g / m ² and a thickness of 0.95 mm in the same manner as in Example 1.

<Example 4>
NBKP: 10%, LBKP: 60%, used paper pulp A: 30% instead of NBKP: 10%, LBKP: 75%, used paper pulp F: 15% as raw materials for the middle layer forming pulp slurry Produced a multilayer paper substrate having a basis weight of 800 g / m ² and a thickness of 0.95 mm in the same manner as in Example 1.

<Example 5>
Other than using NBKP: 10%, LBKP: 60%, recycled paper pulp A: 30%, NBKP: 10%, LBKP; 30%, recycled paper pulp G; 60% as raw materials for the middle layer forming pulp slurry Produced a multilayer paper substrate having a basis weight of 800 g / m ² and a thickness of 0.95 mm in the same manner as in Example 1.

<Example 6>
NBKP: 10%, LBKP: 60%, recycled paper pulp A: 30% instead of NBKP; 10%, LBKP; 10%, recycled paper pulp G; 80% as the raw material for the middle layer forming pulp slurry, the back layer As a forming pulp, a basis weight of 800 g / m ² and a thickness of 0.95 mm were obtained in the same manner as in Example 1 except that LBKP; 50% and waste paper pulp G; 50% were used instead of LBKP; 100%. A multilayer paper base was produced.

<Example 7>
NBKP: 10%, LBKP: 60%, used paper pulp A: 30% instead of NBKP: 10%, LBKP: 40%, used paper pulp G: 50% as the raw material for the middle layer forming pulp slurry, the back layer As a forming pulp, a basis weight of 800 g / m ² and a thickness of 0.95 mm were obtained in the same manner as in Example 1 except that LBKP; 50% and waste paper pulp G; 50% were used instead of LBKP; 100%. A multilayer paper base was produced.

<Example 8>
NBKP: 10%, LBKP: 60%, recycled paper pulp A: 30%, but NBKP: 10%, LBKP; 40%, recycled paper pulp H; 50% as raw materials for the intermediate layer forming pulp slurry Produced a multilayer paper substrate having a basis weight of 800 g / m ² and a thickness of 0.95 mm in the same manner as in Example 1.

<Comparative Example 1>
As in Example 1, except that NBKP; 10%, LBKP; 60%, waste paper pulp A; 30%, NBKP; 10%, LBKP; 90% were used as raw materials for the intermediate layer forming pulp slurry. A multilayer paper substrate having a basis weight of 800 g / m ² and a thickness of 0.95 mm was manufactured.

<Comparative example 2>
In the same manner as in Example 1 except that NBKP; 10%, LBKP; 60%, waste paper pulp A; 100% was used instead of 30% as the raw material for the middle layer forming pulp slurry. A multilayer paper substrate having an amount of 800 g / m ² and a thickness of 0.95 mm was produced.

<Comparative Example 3>
In the same manner as in Example 1, except that NBKP; 10%, LBKP; 60%, waste paper pulp A; 30%, and waste paper pulp D; 100% were used as raw materials for the middle layer forming pulp slurry. A multilayer paper substrate having an amount of 800 g / m ² and a thickness of 0.95 mm was produced.

<Comparative Example 4>
Other than using NBKP: 10%, LBKP: 60%, recycled paper pulp A: 30%, NBKP: 10%, LBKP; 40%, recycled paper pulp E; 50% as raw materials for the middle layer forming pulp slurry Produced a multilayer paper substrate having a basis weight of 800 g / m ² and a thickness of 0.95 mm in the same manner as in Example 1.

<Comparative Example 5>
Other than using NBKP: 10%, LBKP: 60%, recycled paper pulp A: 30%, NBKP: 10%, LBKP; 40%, recycled paper pulp I: 50% as raw materials for the middle layer forming pulp slurry Produced a multilayer paper substrate having a basis weight of 800 g / m ² and a thickness of 0.95 mm in the same manner as in Example 1.

<Comparative Example 6>
NBKP: 10%, LBKP: 60%, used paper pulp A: 30% instead of NBKP: 10%, LBKP: 20%, used paper pulp J: 70% as raw materials for the middle layer forming pulp slurry Produced a multilayer paper substrate having a basis weight of 800 g / m ² and a thickness of 0.95 mm in the same manner as in Example 1.

[Composition of multilayer paper substrate]
About the multilayer paper base material of the said Examples 1-8 and Comparative Examples 1-6, the waste paper pulp ash content, the waste paper pulp compounding ratio of the middle layer and the back layer, the waste paper pulp compounding ratio of the multilayer paper base material, and the multilayer The ash content of the paper base material, the mass average particle diameter of the inorganic filler, the content of the inorganic filler having a particle diameter of 50 μm or more, and the proportion of fine fibers in the inner back layer were determined and summarized in Table 2.

<Measurement of ash content>
The ash content of the waste paper pulp and the multilayer paper base material was determined according to the following formula by firing the sample at 525 ° C. and measuring the mass of the residue according to JIS P 8251.
β = (P / Q) × 100 (%)
Here, β is ash, P is the mass of the residue after firing, and Q is the dry solid content before firing.

<How to find the percentage of recycled paper pulp in the middle layer, back layer and multilayer paper base>
The ratio of waste paper pulp was obtained from the following formula.
α = (M / N) × 100 (%)
Here, α is the waste paper pulp content, M is the dry solid mass of the used paper pulp, and N is the dry solid mass of the total pulp used.
In addition, the used paper pulp compounding rate of a multilayer paper base material becomes substantially equivalent to the total content of the used paper pulp fiber and the inorganic filler in the multilayer paper base material.

<Mass average particle diameter of inorganic filler, how to determine the content of inorganic filler having a particle diameter of 50 μm or more>
An area of 0.95 mm x 10 mm in the cross section of the multilayer paper substrate is continuously photographed with a scanning electron microscope (S3600N manufactured by Hitachi High-Tech Manufacturing & Service Co., Ltd.). More than 100 fillers were extracted. And the mass average particle diameter was calculated | required according to said Formula 2, and content of the inorganic filler whose particle diameter is 50 micrometers or more was calculated | required according to said Formula 3.

<Measurement of the ratio of ultrafine fibers in the inner layer>
The ratio of ultrafine fibers in the inner and lower layers was determined by performing pulp disintegration on the inner and lower layers of the multilayer paper base material using a standard method using a lab disintegrator, and a fiber length distribution measuring device “Fiber Lab” manufactured by Kajaani. The fiber length distribution was measured using The number of measured fibers was 10,000 or more.
The inner and lower layers were collected as follows.
A multilayer paper base material slit into a tape shape with a width of 8 mm was immersed in tap water for a whole day and night, and the paper was sufficiently wetted.

[Evaluation of multilayer paper substrate]
About the multilayer paper base material manufactured in the said Examples 1-8 and Comparative Examples 1-6, mold abrasion property, Z-axis intensity | strength, cavity formation precision, and paper dust generation | occurrence | production prevention property were evaluated with the following method. The evaluation results are shown in Table 3. In addition, the following measurement and evaluation were performed after performing the pre-processing which adjusted the paper-made multilayer paper base material to the state of temperature 23 degreeC +/- 1 degreeC and relative humidity 50% +/- 2% according to JISP8111.

<Evaluation of mold wear>
Cavity-unformed multilayer paper base material slit into a tape shape with a width of 8 mm was continuously punched out at 3 million locations at intervals of 2 mm in accordance with JIS C 0806-3 using an ACP505S punching machine manufactured by Nippon Automatic Machine Co., Ltd. A cavity was formed. At that time, a new mold immediately after polishing was used as the mold. In addition, the cavity shape was 1.12 mm in the width direction and 0.62 mm in the flow direction.
Then, the cross-sectional portion of the cavity of the 3 millionth shot was observed with a magnifying glass to examine the occurrence of chipping, and the die wear was evaluated based on the chipping occurrence. The grades (grades) for visual evaluation are as follows, and grades 1 and 2 are practically usable levels.
Grade 1: No cracks are observed (no mold wear).
Grade 2: 1-3 marks are found in the width of 1.12 mm side (there is slight mold wear).
Grade 3: 4-10 pieces of cracks are seen in the width of 1.12 mm (there is some mold wear).
Grade 4: 11 to 20 pieces of cracks are observed in a width of 1.12 mm (there is considerable mold wear).
Grade 5: 20 or more cracks are observed in a width of 1.12 mm (the mold wear is severe, and polishing or replacement is necessary).

<Measurement of Z-axis strength>
Z-axis strength was measured according to TAPPI standard test method T506. When the Z-axis strength is 200 N / (25 mm) ² or more, delamination hardly occurs even if bending stress occurs when the storage board is wound around the reel.

<Evaluation of cavity formation accuracy>
The cavities for 20 times before the 3 millionth punching in <Mold wear evaluation> were each photographed with a stereomicroscope from the surface side. An example of the photograph taken is shown in FIG. The black part in this photograph is the cavity, and the surrounding area is the surface of the storage board.
About the photograph of each cavity, the narrowest length of the flow direction was measured and the cavity formation precision was evaluated. The longer the narrowest length in the flow direction of the cavity, the lower the unevenness height and the higher the cavity forming accuracy.
Here, the narrowest length in the flow direction of the cavity is shown in FIG. 3 which schematically shows the photograph of FIG. 2, and the most protruding portions 31 and 31 in the cavity inner wall surfaces 30 and 30 facing each other perpendicular to the flow direction. The length b is parallel to the flow direction.
Evaluation is as follows. Evaluations ◎, ○, and △ are practically usable levels.
Evaluation A: The average value (n = 20) of the narrowest length b in the flow direction of the cavity is 0.58 mm or more.
Evaluation (circle): The average value (n = 20) of the narrowest length b of the flow direction of a cavity is 0.56 mm or more and less than 0.58 mm.
Evaluation (triangle | delta): The average value (n = 20) of the narrowest length b of the flow direction of a cavity is 0.54 mm or more and less than 0.56 mm.
Evaluation x: The average value (n = 20) of the narrowest length b in the flow direction of the cavity is less than 0.54 mm.

<Paper dust generation prevention evaluation method>
A storage board for 1000 m before the 3 millionth punching in <Mold wear evaluation> was collected. This storage board was unwound at a speed of 2400 tact / min by TWA6601 manufactured by Tokyo Wells without attaching the top cover tape and inserting the components into the cavity. After unwinding, paper dust generation in the cavity and fiber detachment were visually evaluated. Evaluation is as follows. Evaluations ◎, ○, and △ are practically usable levels.
Evaluation A: Paper dust was hardly generated.
Evaluation ○: Paper dust was slightly generated.
Evaluation Δ: Paper dust was slightly generated.
Evaluation x: A large amount of paper dust was generated.

  A multilayer paper base material is produced using waste paper pulp, and the content of the inorganic filler with a mass average particle diameter of the inorganic filler of less than 50 μm and a particle diameter of 50 μm or more is less than 40%, and the recycled paper pulp blend of the multilayer paper base material In Examples 1 to 8 in which the rate is 5 to 70% (that is, the total content of the waste paper pulp fiber and the inorganic filler in the multilayer paper base is 5 to 70%) and the ash content is 1 to 15%, Mold wear was prevented. Further, the Z-axis strength and the cavity forming accuracy were high, and the generation of paper dust was prevented.

On the other hand, in Comparative Example 1 in which a multilayer paper base material was produced without using waste paper pulp, the mold was easily worn and the cavity formation accuracy was low.
A multilayer paper base was produced using waste paper pulp. In Comparative Example 2 where the percentage of waste paper pulp in the multilayer paper base was more than 70%, the cavity formation accuracy and Z-axis strength were low, and the occurrence of paper dust was also observed. It was.
In Comparative Example 3 in which the inorganic filler has a mass average particle size of 50 μm or more, the content of the inorganic filler having a particle size of 50 μm or more is 40% or more, and the ash content is higher than 15%, the mold is easily worn and the Z-axis strength is increased. In addition, the accuracy of cavity formation was low, and paper dust was easily generated.
In Comparative Example 4 in which the content of the inorganic filler having a particle diameter of 50 μm or more was set to 40% or more, the mold was easily worn, the cavity formation accuracy and the Z-axis strength were low, and paper dust was easily generated.

DESCRIPTION OF SYMBOLS 1 Multilayer paper base material 10 Surface layer 20 Middle back layer 21 Middle layer 22 Back layer

Claims (1)

A used paper pulp manufacturing process for manufacturing a used paper pulp containing pulp fibers and inorganic fillers from a used paper, and a paper making process for making a multilayer paper substrate using fresh pulp and used paper pulp,
In the waste paper pulp manufacturing process, waste paper containing 5% by mass or more of inorganic filler as ash is disaggregated and dust-removed, and then the weight average particle diameter of the inorganic filler is less than 50 μm, and the particle diameter occupied by the inorganic filler Dispersing using a hot disperser so that the content of inorganic filler of 50 μm or more is less than 40% by mass,
In the papermaking process, the waste paper pulp is used for papermaking of layers other than the surface layer, and the total pulp fiber contained in the layer other than the surface layer is a fiber length distribution in which the proportion of fine fibers having a length of 0.2 mm or less is 20 to 70%. A method for producing a multilayer paper base material for chip-type electronic component storage board, wherein waste paper pulp is blended so as to have
However, the fiber length distribution is the fiber length of the measurement sample disaggregated by the pulp disaggregation method of JIS P8220. 52 is a fiber length distribution measured by a pulp fiber length test method using an optical automatic measurement method defined in 52 and obtained on the basis of a number.