JPH03249300A - Paper board for chip-like electronic part carrier tape - Google Patents

Abstract

PURPOSE:To provide the subject paper board having specific thickness, Z axial strength, taper stiffness and equilibrium moisture and not delaminated or folded by the bending or wiping operation in the inversion process of a high speed automatic machine by processing bleached kraft paper, etc., into the multi- layered paper board. CONSTITUTION:Pulp such as bleached kraft pulp preferably having a beating degree of 250-500ml is mixed with a paper-reinforcing agent such as starch and processed into paper board, followed by spraying a modified starch between the layers of the paper board to provide the objective paper board having a thickness of 0.5-1.1mm, a density of <=0.8g/cm<3>, a Z axial strength of >=25kgf/in<2>, an equilibrium moisture of 8.5-10.5% and a taper stiffness satisfied with the equation ((y) is taper stiffness; (t) is thickness; (x) is Z axial strength).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a paperboard used for a chip-shaped electronic component carrier tape.

[Prior Art] In recent years, in response to the increasing popularity of electronic devices, the demand for ultra-small chip components of 1 to 2 J* square has been rapidly increasing.

Packaging forms for transporting chip components include bulk packaging (bulk packaging), magazine packaging (overlapping alignment), and gear tape packaging. Among them, carrier tape packaging is
Compared to other methods, it has excellent reliability and suitability for continuous automatic work. Materials for the carrier tape include plus book and paper, but paper is the most desirable from the viewpoints of manufacturing cost, overlapping of tapes, and industrial waste.

Paper carrier tape is a continuous band-like strip with intermittent holes for storing chip components, and the surface is covered with a film. After the chip components are placed in the hole, the surface and cover film are sealed.

The carrier tape containing the chip components is transported in the form of a reel, and in the process of using the chip components, the chip components are removed and used by an automatic machine while continuously peeling off the surface film.

All of these processes are operated at high speed by automatic machines.
The carrier tape is used after being unwound from a core having a diameter of 5011III+, and is subjected to a "straining" force that reverses its curl in various automatic machines and machines. If the tape breaks due to bending or squeezing force, it will cause problems such as parts being ejected incorrectly on automatic machines, so it is important to ensure that the paperboard layers do not peel off or the tape breaks during bending and squeezing. This is a required characteristic.

Conventionally, as a method of increasing the interlayer adhesive strength of paperboard, for example, a method of adding a paper strength enhancer such as acrylamide to a valve as disclosed in Japanese Patent Publication No. 53-45411, and Japanese Patent Publication No. 57-1
A method of spraying starch between paper layers as disclosed in Japanese Patent Publication No. 1295, and a method of spraying modified starch and other polymers between paper layers as disclosed in Japanese Patent Application Laid-Open No. 62-257498 are known.

TAPP! is the most typical test method for measuring the adhesive strength between paper layers of paperboard. There is a standard test method T-506, and this measurement value is Z-axis strength (meaning tensile strength in the thickness direction of paper)
Hereinafter, in the present invention, the measured value of interlaminar strength by TAPPJ standard test method T-506 will be referred to as Z-axis strength, and this will be adopted.

Regarding paperboard for chip-shaped electronic component carrier tape, there is Japanese Patent Application Laid-Open No. 59-84762, which was previously proposed by the present applicant, but the strength in the Z-axis direction is 2.78yf/cn+2 or more, that is, 19*gf/in. As described above, the Z-axis strength is insufficient for the subsequent increase in speed of the carrier tape, and under severe conditions such as bending and ironing when using the carrier tape, delamination often occurs and the tape breaks. there were.

[Problems to be Solved by the Invention] The present invention solves the above-mentioned problems, and is a high-speed automatic machine that uses a carrier tape to store and take out chip-shaped electronic components, and is capable of handling forces such as bending and ironing. To provide a paperboard for a chip-shaped electronic component carrier tape that does not cause delamination or folding even when the layers are removed.

[Means for Solving the Problems] As a result of various studies regarding the above-mentioned problems, the present inventors have found that in order to withstand severe conditions such as bending and ironing when using a carrier tape, it is necessary to improve the 7-axis strength. It was discovered that flexibility and durability against bending and ironing can be increased by controlling the stiffness of paper, or the so-called stiffness of paper, to an appropriate range depending on the thickness, and this led to the completion of the present invention.

That is, the present invention has a thickness of 05 to 1.1 m and a density of 0.8
In multilayer paperboard with q/cI of 13 or less, TAPPI
Z-axis strength specified by standard test method T-506 is 25 kg
f/n2 or more, and the taper stiffness (vertical direction) y defined in JISP8125 is equal to the thickness t and the Z-axis strength X
This is a paperboard for chip-shaped electronic component carrier tape, which satisfies the relational expression y<1560t 2+20x-360 and has an equilibrium moisture content of 8.5 to 10.5%.

The paperboard of the present invention has a thickness of 0.5 to 11jIII.
Those in the + range are used. Depending on the thickness of the chip components to be accommodated in the holes provided in the paperboard, a paperboard with a thickness of less than 0.5 am may be used, but if the thickness is less than 0.5 am, delamination will not occur, and as in the present invention, There is little need to lower the stiffness. Paperboard with a thickness exceeding 1.1M is difficult to make with a normal paper machine, and since the present invention is directed to type III chip components, it is not a target of the present invention. The multilayer paperboard of the present invention needs to have a density of 0.8 g/cm3 or less. The seven-axis strength required for the paperboard of the present invention increases as the density increases, but the stiffness also increases at the same time, resulting in a paper that is hard and difficult to handle. Since dense and hard paper loses its flexibility, it is used in the carrier tape of the present invention and is wound around a 50# diameter glue, which is then bent and squeezed while being unwound. Since delamination and folding are likely to occur during the process, the paperboard used in the present invention has a density of 0.8 (J/(1j) or less).

The paperboard for chip-shaped electronic component carrier tape of the present invention has Z
It is necessary that the shaft strength is 25 kgf/in2 or more. As mentioned above, automatic machines that fill carrier tapes with chip-shaped electronic components and unseal and take them out have recently become faster, and the Z-axis strength of conventional multilayer paperboard has increased to 25 kgf/in.
Furthermore, according to the study results of the present inventors, when the Z-axis strength is less than 25 kgf/
It has also been found that even if in 2 or more, if the rigidity is high, delamination and folding are likely to occur.

Although the stiffness must be lower than a specific value, it has been found that this value is not determined as an absolute value, but has a certain relationship with the thickness of the paper and the Z-axis strength.

If the Z-axis strength is high, the rigidity may be high, but if the Z-axis strength is not so high, the rigidity must be lowered.

In addition, in the case of paper of the same quality, especially if it has the same 7-axis strength, as the thickness increases, the stiffness generally increases in proportion to the cube of the thickness, so even if the paper is thin and does not cause delamination, the stiffness increases Stiffness increases rapidly, causing delamination.

As a result of research into these relationships, the present inventors found that the stiffness that is the limit for preventing delamination of multilayer paperboard, that is, the taper stiffness (longitudinal direction) y, is determined by the paper thickness t and 7 It has been found that it is preferable that the relationship with the shaft strength X be a value determined by the following formula.

V < 1560t 2+ 20X -360 example Eva,
Paperboard (7) Fj [st = 0.966jw*, Z-axis strength If the rubbing and peeling were good, y = 1.60 Kgf/Ci was calculated from the above formula, and the measured taper stiffness was 1.53, and gr/Ci was smaller than the calculated value, satisfying the above formula. This results in good agreement with actual usage results.

Next, preferred materials and manufacturing conditions for manufacturing the paperboard for carrier tape of the present invention will be explained.

The valves used in the present invention are those normally used for each layer of paperboard, but in the present invention,
In particular, since the cover tape is peeled off and used after sealing the synthetic resin cover tape as described above, a strong surface layer is required, so BKP (bleached kraft valve) is used. In particular, in consideration of the balance with the stiffness of the paper, it is preferable that the ratio of NBKP (softwood bleached kraft bulb) and LBKP (hardwood bleached kraft bulb) be used in a range of 8=2 to 2:8. The freeness of the valve is Canadian standard freeness (C
8F) and a range of 250 to 500 m fJ is suitable.

In order to improve the interlayer strength of the valves in the middle and back layers, it is necessary to make them as soft as the surface layer, but since surface strength is not required, DIP (deinked waste paper pulp) can be blended.

Since DIR lowers the equilibrium moisture content, it is also effective in this respect. For the same reason, TMP (thermomechanical valve),
It is also possible to blend CTMP (Chemical Thermo Mechanical Valve Calgrand Valve) or the like. It is necessary to internally add a paper strength agent such as starch, modified starch, or polyacrylamide to each layer to increase interlayer strength and prevent folding, but if used too harshly, the stiffness increases too much and the interlayer strength becomes strong. However, delamination is likely to occur due to ironing.

For this reason, the paper strength enhancer is preferably added in an amount of 3 to 6% (solid content) to the valve, although it varies depending on the type of chemical.

Furthermore, in order to ensure that the Z-axis strength is 25 kgf/in'' or higher, it is desirable to spray starch (including modified starch) between each layer, but for the same reason as above, starch is sprayed between each layer of paperboard in total. It is necessary to set the amount to about 7 to 15 g/TIt (solid content).

As mentioned above, in order to keep the Z-axis strength and stiffness within the range of the present invention, the valve composition, beating degree, paper strength enhancer, interlayer adhesive,
It is necessary to set conditions within an appropriate range and use and implement them in combination.

As mentioned above, delamination due to ironing can be defined only by the paper thickness, Z-axis strength, and stiffness, and changing the preparation and papermaking conditions appropriately depending on the thickness is a part of normal paper mill operating technology. It will be implemented based on

Another characteristic required of carrier tapes is the equilibrium moisture content of paper. This is because when paperboard tape is coated with synthetic resin film on both the front and back sides as mentioned above, if there is a change in temperature, the water in the paper evaporates and condenses, which is one of the causes of rust on chip parts. . In addition, if the equilibrium moisture content is too low, the Z-axis strength and stiffness measured under standard conditions will change during drying, making it easier to break, so the limitations on 7-axis strength and stiffness in the present invention are meaningless during drying. become. For this reason, it is necessary that the equilibrium moisture content of paper is in the range of 8.5 to 105%.

If the equilibrium moisture content is less than 8.5%, the paper's rigidity will become too high in the direction of the Z-axis strength, and it will easily break due to ironing.On the other hand, if it exceeds 105%, it will be difficult to change the temperature when the chip parts are stored and sealed. It is undesirable if there is condensation, which can cause rust on chip parts.

As described above, in the present invention, the most important factor for paperboard delamination is the Z-axis strength, but if the paper quality is the same, especially the same biaxial strength, and the thickness increases, the interlayer delamination will occur when subjected to ironing force. This was completed based on the knowledge that peeling easily occurs.

It is not clear why delamination does not occur when the above-mentioned relationship between the stiffness, thickness, and Z-axis strength of the paper of the present invention is satisfied, but when the stiffness is high, the squeezing force acts in a straight direction to peel the layers. On the other hand, it is assumed that a material with low rigidity absorbs the squeezing force and weakens the force in the direction of peeling the layers.

By providing the paperboard for carrier tape of the present invention, a carrier tape for chip-shaped electronic components that is thick, has a not very high density, and does not cause delamination or folding even when subjected to high-speed mechanical straining force can be put into practical use. It became possible to make it into

[Example 1 Examples of the present invention are listed below.

Example 1 Surface layer NBKP 70%, LBKP 30%, freeness 420af! .

Medium IINBKP 40%, LBKP40%, THP2
0%1-freeness 310IIli! , back layer LBKP 50
%, DIP 50%, and the freeness is 380 d, and 5% paper strength enhancer polyacrylamide is added to the pulp (same below the solid content), fixed with sulfuric acid band, sent to the paper making process, and wetted in the paper machine. Concentration 35 between each layer in part
% starch aqueous solution was sprayed onto the layers so that the total between each layer was 9 g/TIt (same below the solid content), and the basis weight was 74.
09/rd multilayer paperboard was made to obtain the paperboard for carrier tape of the present invention.

Example 2 In Example 1, the surface layer has a freeness of 4007 FIJ, the middle layer has a freeness of 310 tiles with NBKP of 60% and DIR of 40%.
The paper strength enhancer is 4% of the pulp, and the starch is 11g/Td.
A paperboard for a carrier tape of the present invention was obtained in the same manner as in Example 1, except that a multilayer paperboard of 1590 g/TIl was made by spraying.

Example 3 In Example 1, the surface layer freeness was 350mj, the paper strength enhancer was 4% based on the pulp, and the starch was sprayed at 11g/i.
A paperboard for a carrier tape of the present invention was obtained in the same manner as in Example 1, except that a multilayer paperboard with a basis weight of 4509/1 d was made.

Comparative Example 1 In Example 1, middle II NBKP 40%, DIP
A multilayer paperboard was obtained in the same manner as in Example 1, except that the paper strength was 60%, the freeness was 400 mJl, and the paper strength agent was 7% based on the pulp.

Comparative Example 2 In Example 2, middle layer NBKP 40%, DIP 60
%, the freeness was 400 mN, and a multilayer paperboard was obtained in the same manner as in Example 2, except that the paper strength enhancer was 7% based on the pulp.

Comparative Example 3 In Example 3, medium I NBKP 40%, DIP 6
A multilayer paperboard was obtained in the same manner as in Example 3 except that the starch content was 0%, the freeness was 400 mfl, and the starch was 7 g/m.

Comparative Example 4 A multilayer paperboard was obtained in the same manner as in Comparative Example 1 except that the paper strength enhancer was 25% based on the pulp and the starch was 6 g/bottom.

Moisture Test 1 The multilayer paperboard obtained in Example 1 was adjusted to have a moisture content of 75% and used as a sample.

Moisture Test 2 The multilayer paperboard obtained in Example 1 was adjusted to have a moisture content of 11.5% and used as a sample.

Using the multilayer paperboards obtained in the above Examples and Comparative Examples as samples, physical property tests were conducted according to the following test methods, and the results are shown in the table.

(1) Ironing Peeling Test Take a sample with a width of 811 m and a length of 200 as+ from the paperboard, place it on a flat surface, and use the center line in the width direction at 1/2 of the length of 200 #I as a fulcrum. After bending 180゜,
Subsequently, the film was returned to the opposite direction by 180° and the state of interlayer peeling was visually evaluated.

No peeling or peeling only at the bent part...Grade 1 Peeling within 5 front and rear shoes from the folded part...Grade 2 Peeling at a position beyond 5 JII from the folded part Grade 3 (2) Stiffness According to the taper stiffness test specified in JISP8125 Measurement (3) Z-axis strength Measurement according to TAPPI standard test 506 (4) Equilibrium moisture The sample is placed in a constant temperature and humidity chamber under conditions to achieve the specified equilibrium moisture.
After controlling the humidity for 4 hours, the moisture content was measured according to the JISP8127 test method.

From the results shown in the table, the paperboard for carrier tape of the present invention is superior to the paperboard with high rigidity in terms of thickness and Z-axis strength of the comparative example, with all practical peel test evaluations being grade 1. . Therefore, it is clear that a multilayer paperboard that satisfies the relational expression between thickness, Z-axis strength, and stiffness found in the present invention can be suitably used as a paperboard for carrier tapes without peeling or folding due to ironing.

The graph showing the limit curve of taper stiffness from the relationship between thickness and Z-axis strength is shown in the drawing.

For example, when the thickness of Example 1 is 0.948 am+ and the Z-axis strength is 27.3 gf/in2, the limit value of the taper stiffness is approximately 1.5 gf/l:i, and the taper stiffness is 1. To 5! If it is Jf/ci or less, it can be assumed that the paperboard is in good condition without peeling due to ironing, and the actual value of 140 (lf/- supports this).

[Effects of the Invention] The paperboard for chip-shaped electronic component carrier tape of the present invention has unprecedentedly high Z-axis strength, high interlayer peel strength, and a constant ratio between Z-axis strength, thickness, and stiffness. Having discovered this relationship, we were able to achieve high-speed chip component storage and
It was possible to obtain a paperboard for a rear table of a chip-shaped electronic component 17 that does not cause delamination or folding even when subjected to the force of bending and ironing in a take-out device.

[Brief explanation of drawings]

The drawing is a graph showing an example of the relationship between the thickness, taper stiffness, and Z-axis strength of the paperboard for chip-shaped electronic component carrier tape of the present invention.

Claims (1)

[Claims] 1. Thickness 0.5-1.1mm, density 0.8g/cm^
For multilayer paperboard of 3 or less, the Z-axis strength specified in TAPPI standard test method T-506 is 25 kgf/in^
2 or more, and the taper stiffness (vertical direction) y specified in JISP8125 is a value that satisfies the relational expression y<1560t^2+20x-360 between the thickness t and the Z-axis strength x, and the equilibrium moisture content is 8. A paperboard for a chip-shaped electronic component carrier tape, characterized in that the content is 5 to 10.5%.