CN1222449C - Cushioning body for glass substrate and packing body using the cushioning body - Google Patents

Abstract

A cushioning body for glass substrate having an L-shaped section and the thickness of the L-shaped section at the end part larger than the thickness thereof at the corner part, wherein (1) the thickness of the cushioning body is gradually decreased from the end part to the corner part of the L-shaped section with the bottom part of a fixture guide groove taken as a reference by forming the fixture guide groove so that the depth thereof is gradually increased from the end part to the corner part of the L-shaped section, (2) the cushioning device is formed so that the thickness of the cushioning body itself is gradually decreased from both end parts to the corner part of the L-shaped section without forming the fixture guide groove, and (3) a projected part is formed at both outer end parts of the L-shaped section of the cushioning body, whereby a fixture tightening force is prevented from being concentrated to the corner part when the cushioning body is tightened with a fixture.

Description

Buffer for glass substrate and packaging product using same

technical field

The present invention relates to a buffer body for protecting glass substrates, including a glass substrate having electronic parts such as semiconductor devices formed thereon, from damage due to vibration during transportation. The present invention also contemplates a packaged product, wherein a plurality of the above-mentioned glass substrates are packaged together.

Background technique

In recent years, electronic or electrical devices, especially liquid crystal displays or plasma displays as a peripheral device for personal computers, and portable terminal devices represented by mobile phones, have developed along with the development of the information technology industry represented by the Internet. Became a device for a surge in production. There is a keen desire to develop technologies related to cushioning bodies for packaging or shipping these devices. Regarding the device, a glass substrate having electronic parts formed thereon such as a semiconductor device such as a TFT liquid crystal element for a color filter (a substrate having a circuit formed thereon in which Glass substrates incorporating thin-film transistors) and liquid crystal panels are so thin that they are vulnerable to shock or vibration during transportation, and because of their extremely fine structure, they are so susceptible to external influences that it is difficult to deal with. In particular, in the case of outputting a glass substrate before processing or a semi-finished product before forming a finished product, the above-mentioned electronic parts have already been set thereon, and thus they are more strongly adversely affected by static electricity or dust, so that in some cases lose their function.

Therefore, many packaging techniques have been proposed for safe transportation of glass substrates without causing damage.

As an example, a technique is disclosed in Japanese Patent Laid-Open No. 319456/1993. The gist of this technology is a cushioning body that includes a polyolefin bead-like foam with special properties, and has a roughly L-shaped cross section, and has a plurality of substrate insertion grooves on the inner side surface along the L-shape . On the packaged glass substrate, a plurality of glass substrates are arranged in parallel with each other at predetermined intervals to form a cuboid, and each corner of each substrate is inserted into the substrate insertion groove of the buffer body so that the four sides of the parallel cuboid are aligned with the substrates. The surface is inserted into the damping body at right angles and can then be fixed, if desired, with a fastening element, such as a rubber band or a strap.

However, in the case of using a fixing member such as a rubber band or a tape to fix on the outside of the buffer body, its binding force is concentrated on the corners of the buffer body, so that the L-shape of the buffer body is widened and the glass substrate is separated from the substrate. Inserted into the slot, so the protective function cannot be fully exerted.

Also, in the aforementioned L-shaped buffer body, the width of the substrate insertion groove is the same as or slightly narrower than the thickness of the glass substrate, and the polyolefin bead-shaped foam is compressed, which is a bead characteristic of high elastic recovery force against the glass. The substrate is fixed. Therefore, although the generation of dust due to the vibration and friction of the glass substrate can be effectively prevented during transportation, the frictional resistance with the glass substrate has an adverse effect on the glass substrate packaging as an essential purpose. When the glass substrate is forcibly inserted into When placed in a groove, a glass substrate having a thickness as thin as about 0.4 to 1.0 mm tends to bend and is easily damaged. Therefore, there arises a problem that it takes a long time if very careful operations are performed in order to avoid such damage. The same is true for unsealing the substrate. In particular, from the viewpoint of labor saving, automatic packaging equipment and unsealing equipment have recently been introduced, but the above-mentioned problems are prone to failure, and it has been pointed out that the L-shaped cushioning body is actually not suitable for automation.

Furthermore, there is another problem that fine abrasion marks may be generated on the surface of the glass substrate due to frictional resistance as the glass substrate is inserted into the substrate insertion groove.

In view of the above-mentioned problems, an object of the present invention is to provide a buffer body for glass substrates, which prevents the glass substrates from leaving the groove at the L-shaped end of the buffer body when the glass substrates are packaged, and even It safely protects the glass substrate when external forces such as vibration or drop shock are applied to it during transportation or handling. Furthermore, another object of the present invention is to provide a buffer body for glass substrates, which is suitable for automatic packaging and unsealing of glass substrates, is not prone to dust generation even when sliding friction with glass substrates, and has the ability to use Excellent durability for several times. Furthermore, an object of the present invention is to provide a packaging product formed by using the cushioning body.

Overview of the invention

In a first aspect, a buffer body for a glass substrate according to the present invention comprises a polyolefin bead foam, and has a substantially L-shaped cross-section conforming to the shape of the corner of the glass substrate, on its inner surface A plurality of substrate insertion grooves are formed along the L-shape for fixing both sides of the glass substrates forming the corners, and at least one fixture guide groove is formed along the L-shape on the outer surface thereof, wherein the bottom of the groove is guided with the fixture The thickness of the base buffer body gradually decreases from the two ends of the L shape to the central part.

As a preferred embodiment, the above-mentioned first buffer body of the present invention includes an embodiment, wherein the bottom of the guide groove of the fixing member is inclined at a corner.

In the second aspect, a buffer body for a glass substrate according to the present invention comprises a polyolefin bead foam and has a substantially L-shaped cross-section conforming to the shape of the corner of the glass substrate, on its inner surface A plurality of substrate insertion grooves are formed along the L-shape for fixing both sides of the glass substrate forming corners, wherein the thickness of the buffer body gradually decreases from both ends of the L-shape to the center.

In a third aspect, a buffer body for a glass substrate according to the present invention comprises a polyolefin bead foam and has a substantially L-shaped cross-section conforming to the shape of the corner of the glass substrate, on its inner surface A plurality of substrate insertion grooves are formed along the L shape for fixing both sides of the glass substrate forming corners, wherein protrusions are formed outside both ends of the L shape.

As a preferred embodiment, the above-mentioned second and third buffer bodies for glass substrates according to the present invention include an embodiment in which one of the outer corners is inclined.

In addition, as a preferred embodiment, the above-mentioned buffer body of the present invention includes: in one embodiment, a notch is formed on the inner side of the buffer body along a direction at right angles to the insertion groove of the substrate; in one embodiment, the buffer body has 10 The maximum thickness of up to 60mm, and the ratio of the two sides of the L shape based on the shorter side is 1.0 to 3.0, and the width of the substrate insertion groove is approximately 1.0 to 4.0 times the thickness of the glass substrate, and the depth is 3 to 15mm, and the groove The pitch is 6 to 100 mm; and in another embodiment, wherein the polyolefin bead foam has an average particle size of 1.5 to 5.0 mm shaped particle size, has a fusion rate of 70% or higher, compression elasticity index 3.0 to 490 with a response rate of 60% or greater.

In a first aspect, a packaged product according to the present invention is characterized in that a plurality of glass substrates are arranged parallel to each other at predetermined intervals so as to form a parallel cuboid, corners of the respective substrates are inserted into the first The buffer body substrate is inserted into the groove so that the four sides of the cuboid are inserted into the buffer body at right angles to the surface of the buffer body, and the assembly is bound and fixed by using a long fixing member along the fixing member guide groove of the buffer body.

In a second aspect, a packaged product according to the present invention is characterized in that a plurality of glass substrates are arranged parallel to each other at predetermined intervals so as to form a parallel cuboid, and the corners of the respective substrates are inserted into the second substrate for the glass substrates. Or three buffer body substrates are inserted into the groove so that the four sides of the cuboid are inserted into the buffer body at right angles to the buffer body surface, and the assembly is fixed by binding along the L-shaped outer side of the buffer body with a long fixing piece.

A brief description of the drawings

Fig. 1 is a perspective view of one embodiment of a cushioning body according to the present invention.

Figure 2 is a perspective view of one embodiment of a packaged article according to the present invention.

3(a) to 3(e) are cross-sectional views showing an embodiment of the buffer body according to the present invention.

4(a) to 4(c) are cross-sectional views showing examples of the configuration of the buffer substrate insertion groove according to the present invention.

In addition, in the drawings, reference numeral 1 is a buffer body; 2 is a substrate insertion groove; 3 is a guide groove for a fixing member; 4 is a protrusion; 21 is a glass substrate; 22 is a fixing member; 31 is a wall surface of the buffer body; 32 33 is the end of the L shape; 34 and 34' are the corners of the L shape; 35 is the bottom of the guide groove of the fixing member; 36 is the inclined part; 37 is the groove; 38 is the protruding part; 39 is a concave part.

Best form for carrying out the invention

The cushioning body of the present invention comprises a polyolefin bead-shaped foam body having a substantially L-shaped cross-sectional shape, said cushioning body being characterized in that its thickness is thicker at the ends of the L-shape than at its corners. thick. Thus, when the packaged glass substrates are formed by bundling the components with the fixings from the outside, the fixings reach a more outward position at the ends of the L shape than at the corners, which serves to prevent the binding force of the fixings Concentrate on the corners and press the binding force evenly on the entire buffer body to protect the glass substrate.

In the present invention, a specific structure in which the buffer body is thicker at the ends of the L shape than at the corners is as follows.

(1) The shape of the guide groove of the fixing member is such that its depth becomes deeper from the end of the L-shape to the corner, so that the thickness of the buffer body based on the bottom of the guide groove of the fixing member gradually decreases from the end of the L-shape to the corner. ;

(2) The guide groove of the fixing member is not formed, and the cushioning body is molded such that its own thickness gradually decreases from the end of the L-shape to the corner; and

(3) Protrusions are formed outwardly at both ends of the L-shape of the buffer body.

The cushioning body and the packaged product will be specifically described below with reference to an embodiment, wherein a plurality of glass substrates are integrally packaged with the cushioning body.

Fig. 1 is a perspective view showing one embodiment of the cushioning body of the present invention having the structure described in (1) above. In FIG. 1 , reference numeral 1 is a buffer body; 2 is a substrate insertion groove; 3 is a guide groove of a fixing member; 4 is a protrusion separating adjacent substrate insertion grooves from each other.

Fig. 2 is a perspective view showing an example of a packaged product of the present invention, in which a plurality of glass substrates are packaged with four buffer bodies of the present invention. In FIG. 2 , reference numeral 21 is a glass substrate, reference numeral 22 is a fixing member, and the same reference numerals as in FIG. 1 represent the same components.

The buffer body 1 of the present invention is used to protect the corners of the glass substrate 21 and integrally fix a plurality of glass substrates, and two or more, preferably four buffer bodies are used for packaging.

As shown in FIG. 1 , the shock absorber 1 of the present invention has a substantially L-shaped cross-sectional shape corresponding to the corner of the glass substrate, and is formed in a state of being separated from each other by protrusions 4 in order to fix both sides of the corner of the glass substrate. , a plurality of substrate insertion grooves 2 are provided along the L shape.

Also, in the structure described in (1) above, the fixing piece guide groove 3 is formed along an L shape. As shown in FIG. 2 , the fixing member guide groove 3 is used for binding the packaged glass substrates 21 by winding the fixing member 22 along the fixing member guiding groove 3 . In the present invention, in the case where the guide groove 3 of the fixing member is provided, the thickness of the buffer body 1 is changed so that its thickness at the bottom gradually decreases toward the corner. FIG. 3( a ) schematically shows a section of the buffer body in FIG. 1 along the guide groove 3 of the fixing member and the insertion groove 2 of the substrate. In Fig. 3, reference numeral 31 is the outer surface of the buffer body; 32 is the bottom of the substrate insertion groove 2; 33 is the L-shaped end of the buffer body 1; 34 and 34' are the corners of the L-shape; 35 is a fixing member The bottom of the guide groove 3; 36 is an inclined part; 37 is a groove; 38 is a protrusion; 39 is a recess. In addition, in the following description, the thickness at the corner 34 or 34' refers to the thickness of the shock absorber on the shorter side and the longer side at the inner corner of the L shape.

As shown in Figure 3 (a), by forming the guide groove of the fastener, the thickness of the buffer body at the bottom 35 of the guide groove of the fastener gradually decreases from the end 33 of the L shape to the corner 34', so that its depth is at The L-shape is smaller at the ends 33 and larger at its corners 34'. As a result, since a long holder is wound along the holder guide groove after the glass substrate is packaged, the distance from the holder to the glass substrate is larger at the end 33 than at the corner 34', which serves to prevent the fixing The binding force of the piece is concentrated on the corner 34'.

And, in order to prevent the binding force of the fastener from being concentrated on the corner 34' of the bottom 35 of the fastener guide groove, as shown in Figure 3 (b), it is preferred to make a bevel in advance to form an inclined portion 36. By forming the inclined portion 36, the possibility of damage caused by the fixing piece being embedded in the buffer body is eliminated, and the deformation distortion at the corner 34' is reduced, which is used to reduce the pressure of widening the end portion 33 of the buffer body to the outside. force. The inclined portion 36 may be flat or curved.

In addition, as shown in FIG. 3( c), it is preferable to form one or more grooves 37 on the inside of the buffer body along a direction at right angles to the substrate insertion groove (a direction at right angles to the paper surface), so that the grooves 37 The deformation stress of the outwardly widened end portion 33 due to binding with the fixing member is absorbed, and the stress is prevented from spreading toward the end portion 33 . In addition, as shown in FIG. 3( c ), the groove 37 may have a substantially U-shape or a substantially V-shape.

Also, in FIG. 3 , the protrusion 4 is partially cut away at the inner side of the corner portion 34 on the short side to form a recess 39 . This structure is used to prevent the glass substrate from breaking at the most vulnerable corners when subjected to vibration shock or drop shock during transportation. In addition, in the recessed portion 39, it can be used to remove the protrusion 4 from the bottom of the substrate insertion groove. In addition, from the viewpoint of preventing the glass substrate from breaking at its corners, it is preferable to form the concave portion deeper than the bottom portion 32 .

In an example of the invention of the aforementioned structure (2), in an example of structure (3) shown in FIG. 3( d ) and in FIG. Made thicker. In FIG. 3( d ), the thickness of the buffer body itself gradually decreases from the end 33 to the corner 34 of the L-shape. In this case, it is not necessary to specially form the guide groove of the fixing member, and thus the width and binding position of the fixing member can be freely selected. And, in FIG. 3( e ), the protruding portion 38 is formed on the outer side of the end portion 33 of the L shape, so that the thickness of the buffer body is made thicker at the end portion 33 than at the corner portion 34 . The protrusion 38 may be formed integrally with the cushioning body, or may be formed by bonding a separate formed plate to the cushioning body by heat welding or adhesive. In the latter case, the plate can be made of the same or a different material as the damping body.

Also in the structures of FIG. 3(d) and FIG. 3(e), as shown in FIG. 3(b) or 3(c), inclined portions 36 or grooves 37 may be formed as appropriate.

Next, preferred external dimensions of the shock absorber of the present invention will be described.

The ratio of the lengths of both sides of the L shape (the length of the portion in contact with the glass substrate), based on the length of the shorter side, is preferably 1.0 or more, more preferably 3.0 or less. When the ratio is within this range, the longer side and the shorter side are well balanced with each other, and the rectangular glass substrate can be fixed very stably. In addition, the possibility of damage to the glass substrate due to bending is significantly reduced. The ratio is more preferably 2.7 or less.

With a ratio within the above range, the length of the shorter side is preferably 10% or more, more preferably 45% or less, of the length of the short side of the glass substrate to be packaged. Furthermore, it is more preferably 15% or more, and most preferably 40% or less. When the length of the short side of the shock absorber is within the above range, since the shock absorber can sufficiently absorb the impact force is provided, the glass substrate can be prevented from being damaged even when subjected to a drop impact or the like. In addition, since the stress (self weight of the glass substrate) applied to the buffer body is reduced, generation of dust due to contact friction due to vibration can be suppressed during transportation, and thus satisfactory cleanliness can be achieved.

For a buffer body of a certain size, the length of the shorter side is preferably 100 mm or more, more preferably 500 mm or less. The length of the longer side is preferably 100 mm or more, more preferably 500 mm or less. And, although depending on the number of glass substrates to be packaged, the length in the direction perpendicular to the short side and the long side is preferably 150 mm or more, more preferably 600 mm or less.

Considering the size, weight, number of glass substrates to be packaged and the compressive elasticity index of the buffer body of the glass substrate, the maximum thickness of the buffer body of the present invention is preferably 10mm or more, more preferably 60mm or less, more preferably 15mm or larger and/or 40mm or smaller. When the outer dimensions and the maximum thickness are within the above-mentioned ranges, the buffer can serve as a buffer capable of stably fixing all glass substrate products of various sizes, and a buffer for glass substrates before being processed. In addition, they exhibit the function of adequately protecting the glass substrate from shocks during transportation.

And, in the case of forming the guide groove of the fixing member as shown in FIG. 34' is preferably 2 mm or more, more preferably 15 mm or less. When the fixing member guide groove is formed in such a manner that the depth of the fixing member guide groove is within the above range, since when the assembly is bound with the fixing member, the binding force is uniformly applied to the entire length of the short side and the long side of the buffer body Therefore, it is obvious that the position deviation of the fixing member can be prevented, and the legs of the buffer body can be prevented from being widened and deformed, so that the four corners of the glass substrate can be stably fixed. Therefore, the buffer body can perform a satisfactory function of protecting the glass substrate. In FIG. 3( a ), the guide groove of the fixing member is formed all the way to the end portion 33 . The fastener guide groove may be formed so as to form the same plane as the buffer outer wall 31 in the vicinity of the end portion 33 . In this case, the fastener guide groove is spaced apart from the end portion 33 by preferably 10 mm or more. More preferably, the fixing member guide groove is formed in such a manner that the depth gradually increases from a position separated from the end portion 33 by 100 mm or less toward the corner portion 34'. Within this range, the fixing member does not deviate in position during transportation, and by forming the fixing member guide groove from the end portion 33, the same effect can be obtained.

Furthermore, in the case where the thickness of the buffer body itself varies as shown in FIG. , more preferably 3mm or more, most preferably 8mm or less. Also in this case, by forming a buffer body having a uniform thickness from the end portion 33 toward the corner portion 34 up to a position of 10 mm or more, or more preferably 100 mm or less, and the thickness of the buffer body increases from this position to Tapering toward the corner 34, the same effect as described above can be obtained.

Also, in the case of FIG. 3( e ), it is preferable to make the corner portion 34 thinner than the end portion 33 by 1 mm or more, more preferably 10 mm or less. When the corner portion 34 is made thinner, as shown in FIG. 3( e ), a protruding portion 38 is formed near the end portion 33 . The width of the protrusion 38 along the L-shape in this direction is preferably 10 mm or more, more preferably 100 mm or less, still more preferably 20 mm or more, most preferably 80 mm or less.

Further, in the case of forming the inclined portion 36 as shown in FIG. 3( b), the length of the arc or straight line in the L-shaped section is preferably 3 mm or Larger, more preferably 60mm or smaller.

When the inclination is within this range, when the glass substrate is packaged and the assembly is bound by wrapping the fixture around it, and thus the entire buffer body is uniformly pressed to fix the corner of the glass substrate, the fixing member can be avoided. Concentration of binding forces on the corners. Therefore, a more enhanced function of fixing and protecting the glass substrate can be obtained, and in addition, even when the fixing member is applied with a strong binding force, the fixing member can be prevented from being embedded in the buffer body. Therefore, the buffer body can be reused over a long period of time, and a significantly improved durability is obtained.

In the case where grooves 37 are formed as shown in FIG. 3( c), the depth of the grooves is preferably 1/20 or more of the thickness of the buffer body at the portion where the grooves are formed, more preferably 1/2 or less. . The width of the groove is preferably 2mm or more, more preferably 10mm or less. In addition, there are no particular limitations on the position and number of the grooves 37, but the position is preferably at a distance from the corner (the point where the long and short sides are in contact with the glass substrate) side (the length of the portion in contact with the glass substrate). length) or more, more preferably 4/5 or less, and the number thereof is preferably 1 or more, more preferably 3 or less. When the notched groove 37 is formed within the above range, the glass substrate is sufficiently fixed over the entire length of the glass substrate insertion groove without weakening the rigidity of the buffer body. Therefore, the function of protecting the substrate is improved, and at the same time, an effect of further reducing dust generation due to friction with the buffer body is obtained.

Furthermore, in the case of forming the recess 39 as shown in FIG. 3 , it is preferably formed so that the bottom of the recess 39 reaches the recess 32 of the substrate insertion groove, and it is more preferable to consider the size and thickness of the glass substrate and the maximum thickness of the buffer body. The recessed portion 39 is formed at a depth of 1 mm or more and 8 mm or less, more preferably 2 mm or more and 6 mm or less, from the bottom of the substrate insertion groove 32 . Within these ranges, no external force is applied to the weakest corner of the glass substrate, and even if the shock absorber is twisted and deformed by the impact of falling, the possibility of damage to the glass substrate is significantly reduced. In addition, the structural strength of the buffer body can also be maintained sufficiently, and thus the original shape can be maintained even after repeated use. Therefore, the function of fixing and protecting the glass substrate can be exhibited for a long period of time.

The width of the substrate insertion groove formed in the buffer body of the present invention is preferably 1.0 to 4.0 times, more preferably 1.2 to 3.5 times the width of the glass substrate to be packaged. In this range, the work of inserting and taking out the glass substrate manually or with an automatic device can be quickly performed with high efficiency, and the failure of the glass substrate to break during the inserting work is remarkably reduced. In addition, due to the fixing performance of the glass substrate in the substrate insertion groove, friction between the glass substrate and the buffer is sufficiently suppressed even when a vibration shock is applied thereto, so dust is rarely generated and the glass substrate remains clean.

Also, the depth of the substrate insertion groove is preferably 3 mm or more, more preferably 15 mm or less, in view of the size, weight, compressive elasticity index, and width of the substrate insertion groove of the glass substrate. More preferably 5 mm or more, most preferably 10 mm or less. In this range, the glass substrate can be securely fixed in a state of being inserted into the insertion groove even if subjected to vibration shock during transportation or drop shock during handling, and thus the glass substrate can be prevented from coming out of the insertion groove and contact with adjacent substrates. Also, since the portion of the glass substrate in contact with the substrate insertion groove is always in frictional contact with the buffer due to vibration shock during transportation, there is a high possibility of fine scratches being formed on the surface of the glass substrate. Therefore, in the process of processing the transported glass substrate to produce the liquid crystal panel, the portion of the substrate that has been in contact with the buffer body insertion groove is generally cut off in advance. However, when the depth of the groove is within the above range, the area of the portion is very small, and reduction in productivity can be minimized, thus achieving high productivity. Furthermore, since the amount of dust generated by friction between the glass substrate and the buffer body is small, the buffer body is also satisfactory from the viewpoint of cleanliness.

From the type of glass substrate (such as glass itself, color filter, liquid crystal block, liquid crystal, and plasma display panel), the size and weight of the glass substrate, the compressive elastic index of the buffer, the width of the substrate insertion groove, and the automatic Considering the adaptability of inserting and taking out the glass substrate, the pitch of the substrate insertion grooves is preferably 6 mm or more, more preferably 100 mm or less. In this range, the work of inserting or taking out the substrate can be performed easily and safely, and in addition, bending of the glass substrate caused by contact with adjacent substrates due to vibration shock during transportation or drop shock during transportation can be avoided risks of.

Furthermore, in the shock absorber of the present invention, the protrusions that separate adjacent substrates have a cross-sectional shape with a flat top as shown in FIG. 4( a ). However, in consideration of workability when inserting the glass substrate and generation of dust during insertion, it is preferable to use a guide portion formed, for example, in a convex shape ( FIG. 4( b )) or a trapezoidal shape ( FIG. 4( c )) on the upper side of the protrusion. The two-level shape, preferably trapezoidal. Even when the buffer body has been formed with substrate insertion grooves with a narrow pitch, the metal mold for molding the buffer body can be manufactured with high precision. In the drawings, t1 represents the maximum thickness of the buffer body 1; t2 represents the depth of the substrate inserted into the groove; t3 represents the width of the groove; t4 represents the distance between the grooves.

Next, materials for constituting the cushioning of the present invention will be described.

The cushioning body of the present invention comprises polyolefin bead foam. The foam is formed by filling a metal mold of a desired shape with foamable polyolefin beads, heating and cooling the foam with steam, thereby obtaining a molded foam of a desired shape. When a metal mold is used for molding, a metal mold obtained by casting may be used. The casting method can easily and highly accurately produce a metal mold having a complicated structure, and in addition, the production cost is 1/10 or less of that of a metal mold for injection molding, so it is economical and suitable for mass production.

The polyolefin used to form the polyolefin bead foam can be cross-linked or non-cross-linked. Specific examples of resin materials are low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, linear ultra-low-density polyethylene, polyethene produced with metallocene catalysts, and ethylene-vinyl acetate copolymers. Polyethylene resins represented by ethylene; random and block polypropylene copolymer resins formed between copolymerizable components of ethylene, 1-butene or 4-methyl-1-pentene and propylene; by using metallocene Catalysts yield random polypropylene copolymer resins, and compositions obtained by blending two or more of the aforementioned resins.

Among them, polyethylene resins having a resin density of 0.927 g/cm ³ or more are preferable, polyethylene resins having a resin density of 0.970 g/cm ³ or less, and ethylene or butene-1 and propylene Inter-random polypropylene copolymer resins are more preferred. When the density of the polyethylene resin is within the above range, the obtained cushioning body has appropriate physical properties such as rigidity, elasticity and recovery, and has sufficient practical performance such as remarkably improved shape stability, impact when dropped Cushioning, durability for repeated use, and performance against dust generation. Also, in order to obtain a specific compressive elasticity index, the expansion rate of the buffer body can be increased relatively high, which has the effect of reducing the weight and manufacturing cost of the buffer body. In addition, since random copolymerized propylene resins between ethylene or butene-1 and propylene have higher elasticity than polyethylene, they are suitable as buffers for large-sized glass substrates and have excellent shape stability , can maintain their original shape after repeated use for a long time, so it is preferable.

The first requirement for the cushioning body of the present invention comprising polyolefin bead foam is that the foam particles constituting the cushioning body have an average particle size of preferably 1.5 mm or more, more preferably 5.0 mm or less. More preferably, this dimension is 2.0 mm or greater, and most preferably 4.5 mm or less. When the average particle size is within this range, the ratio of the surface area to the volume of a foam particle is so small that the gas (air) pressure reduction in the particle is very small when steam heating is performed during the molding process, therefore, The foam is fully expanded by applying heat. As a result, minute gaps are hardly formed between the foam particles on the surface of the synthetic foam obtained by in-mold injection molding, and when such a buffer is used for conveying a glass substrate, dust in the air does not intrude into it. The section thus obtains excellent cleanliness. Also, in the process of filling the foam-forming particles into the metal mold, they can be uniformly filled into a minute portion of the substrate insertion groove having a very narrow width, and thus it is possible to obtain the same shape and shape as the metal mold. Cushioning body with high precision in matching dimensions.

In addition, the average particle size of the foam beads is obtained by drawing three lines of 100 mm in length on the surface of the in-mold molding, measuring the number of foam particles in contact with the lines, and calculating the average particle size according to the following formula (A) C (mm) obtained value. Also, this value is the average of the values obtained for the three lines.

C＝(1.626×L)/N ... (A)

where L; centerline length (mm);

N: number of particles

A second requirement for the cushioning body of the present invention comprising polyolefin bead foam lies in the physical properties of the cushioning body. That is, the cushioning body needs to have a fusion ratio of preferably 70% or more, a compressive elasticity index of preferably 3.9 or more (more preferably 490 or less), and a recovery ratio of preferably 60% or more.

In addition, the above-mentioned fusion ratio is obtained by forming a slit of about 1 mm in the thickness direction in the cushioning body, folding the cushioning body outward so as to break the cutout, in the depth direction and at The number of intact foam particles and the number of disconnected particles are measured at about 75 mm in the longitudinal direction, and the number of disconnected particles is divided by the number of intact foam particles, and the calculated value is thus expressed as a percentage. In the present invention, when the fusion ratio is 70% or more, properties related to mechanical strength, such as compressive strength and tensile strength inherent to polyolefin bead foam, can be sufficiently realized. That is, since the numerous foam particles constituting the cushioning body are firmly fused into one body, a cushioning body excellent in durability and resilience is obtained. Therefore, in the case of using the buffer body of the present invention to fix and package the glass substrate, the buffer body can fully resist the strong binding force of the fixture, so the glass substrate can be fixed and packaged at a high level, and the possibility of breaking the glass substrate sex is further reduced. Furthermore, there are no minute gaps between the foam particles on the surface of the cushioning body, and the cushioning body sufficiently exhibits non-absorbent properties during washing with water for repeated handling after use, which provides a guarantee of a high degree of water absorption during drying. Excellent advantage in the job.

Also, when the compressive elasticity index of the buffer is within the above range, the polyolefin can exhibit its inherent maximum buffer capacity, and the buffer has a good balance between rigidity and elasticity. In particular, even a large-sized substrate having a glass substrate size of 500 mm×600 mm or more can be stably fixed and protected at a very high level. In addition, since the buffer body has strength sufficient to resist external force applied thereto during transportation or handling, it undergoes only slight deformation and exhibits sufficient durability to allow the buffer body to be repeatedly used over a long period of time. Also, the expansion ratio of the buffer body for obtaining a specific compressive elasticity index can be increased to a higher level to reduce the weight and manufacturing cost of the buffer body.

Furthermore, since the compressive elasticity index is within the above range and the recovery ratio is 60% or more, the cushioning body exhibits excellent durability against repeated use, which is considered to be the greatest characteristic of polyolefin bead foam, and even Deformation can also be minimized when the frequency of use increases.

In addition, the above-mentioned compression elasticity index is a numerical value obtained by dividing the compression elasticity force (N/cm ² ) by the expansion ratio.

The above compressive elastic force is a value determined using a sample whose expansion ratio has been measured at a compression speed of 10 mm/min in accordance with JIS K7220 in the manner described below. Using a sample with a thickness of less than 20mm, pile up multiple samples to form a thickness of about 20mm for measurement.

The expansion ratio is obtained by cutting a flat sample with a width of 50 mm, a length of 50 mm and a thickness of 20 mm from the buffer body, measuring the weight of the sample to the order of 10 mg, and measuring the width, length and thickness of the sample with a vernier caliper. In order to calculate the volume (cm ³ ), it is obtained by calculating the expansion ratio E (cm ³ ) according to the following formula (B).

E=volume/weight (cm ³ /g) ... (B)

The recovery performance is obtained by cutting a flat sample with a width of 50mm, a length of 50mm and a thickness of 20mm from the buffer body, compressing the sample to 50% of its thickness with a compression test device at a compression speed of 10mm/min, and then After plotting with an automatic plotter AG-5000D manufactured by Shimazu Seisaku-sho K.K., immediately remove the load at the same speed, measure the thickness when the load becomes zero, and calculate the recovery ratio R according to the formula (C) shown below (%) obtained. In addition, using a sample with a thickness of less than 20 mm, a plurality of samples are piled up to have a thickness of about 20 mm, and the measurement is performed.

R＝(T1/T0)×100(%) … (C)

Where T0: thickness before testing (mm);

T1: Thickness (mm) after the test (when the load becomes zero).

Next, the packaged product of the present invention will be described. The packaged article of the present invention is formed by packaging a plurality of glass substrates with two or more cushioning bodies of the present invention as a set, preferably in groups of four. That is, a plurality of glass substrates are placed on positions parallel to each other at predetermined intervals so as to form a cuboid, and each corner of each substrate is inserted into the substrate insertion groove of the cushioning body of the present invention so that the four sides of the cuboid are aligned with each other. The substrate surface is inserted into the buffer body at right angles. Then, wrap a long fixing piece around the cuboid along the L-shape of the buffer body for binding. In the case where the buffer body has a guide groove for the fastener, the fastener is wound along the guide groove for the fastener.

Furthermore, as the outermost glass substrate, a dummy glass substrate may be provided.

Next, another embodiment of a glass substrate packaging product using the cushioning body of the present invention, which is different from the above-mentioned packaging product, will be described.

A plurality of glass substrates are placed in parallel positions at predetermined intervals so as to form a cuboid, and each corner of each substrate is inserted into the substrate insertion groove of the buffer body of the present invention so that the four sides of the cuboid are at right angles to the surface of the substrate. inserted into the buffer. Then, wrap a long fixing piece around the cuboid along the L-shape of the buffer body for binding and fixing. After forming the packaged product, the packaged product is wrapped with a heat-shrinkable resin film, and then heat-treated to heat shrink the film, thereby shrink-wrapping the packaged product.

In addition, in the case of encapsulating the packaged product with the above-mentioned heat-shrinkable resin film, the packaged product may be placed in a bag-like or cylindrical film, and preferably after heat-sealing the ends of the film, The film can be heat-shrunk to adhere tightly to the packaging article.

The above-mentioned packaging product has such a characteristic that the packaging product formed by packaging a plurality of glass substrates integrally with the cushioning body of the present invention is shrink-wrapped by a heat-shrinkable film, which makes even for large-sized glass substrates The encapsulation operation of the packaging products is also very convenient, and the encapsulation can be automated. In addition, in the enclosed packaging product, the heat-shrinkable film does not relax at all, and thus the outermost substrate in the packaging product is unlikely to come into contact with the film to contaminate the glass substrate. Therefore, there is no need to employ a dummy substrate, and the buffer can be effectively used. Furthermore, the entire buffer body is pressed from the outside due to shrinkage stress of the film, and thus the buffer body and the glass substrate are integrally fixed, which serves to prevent the glass substrate from leaving the groove or being damaged. In addition, the frictional contact between the glass substrate and the buffer body due to vibration during transportation is reduced, so that scratches or dust deposits on the glass substrate can be prevented and cleanliness of the glass substrate can be maintained.

As the heat-shrinkable resin film used in shrink-wrapping, there are exemplified polyolefin resin films and polyvinyl chloride resin films. However, polyvinyl chloride resins include a large amount of various plasticizers and stabilizers in order to impart processability and flexibility to extrusion film molding due to their properties. These additives can leach onto the surface of the film over time, or can cause very minute amounts to evaporate even at typical temperatures. Therefore, for encapsulated glass substrates, the cleanliness of the work area may be deteriorated, or when encapsulating packaged goods, it may cause a serious contamination problem in which additives adhere to hands and then come into contact with the glass substrate. In addition, although it is preferable to heat-seal the film to seal the packaged product so as to prevent the intrusion of dust from the outside during transportation, polyvinyl chloride resin has poor heat-sealing suitability and requires expensive equipment such as ultrasonic equipment or High frequency sealing equipment. Therefore, it is preferable to use a polyolefin resin film.

As the polyolefin resin film, a single-layer or multi-layer product of cross-linked or non-cross-linked polypropylene resin or polyethylene resin can be used.

The polyolefin resin film has a thermal shrinkage ratio of at least 15% or more, more preferably 90% or less at 120°C in at least one of the longitudinal and transverse directions. More preferably, the thermal shrinkage ratio is 20% or more. Further preferably, the thermal shrinkage ratio in both the longitudinal and transverse directions is 15% or more and 90% or less. When subjected to thermal shrinkage within the range, the packaging product can be tightly shrink-wrapped without loosening, and thus there is no risk of contamination of the glass substrate due to contact between the glass substrate and the film. In addition, the thermal shrinkage ratio is a value obtained by measurement at 120° C. according to ASTM D-2732.

Also, the maximum thermal shrinkage stress at 120° C. is preferably 0.15 N/mm ² or more, more preferably 5 N/mm ² or less in at least one of the transverse direction and the longitudinal direction. More preferably, it is 0.2 N/mm ² or more and 4.5 N/mm ² or less. Further preferably, it is 0.15 N/mm ² or more and 5 N/mm ² or less in both the transverse direction and the longitudinal direction.

When the maximum thermal shrinkage stress at 120°C is within the above range, the packaging product can be tightly shrunk and wrapped without loosening, and the film is not easy to contact with the glass substrate, so the cleanliness of the glass substrate can be maintained. In addition, since the thermal shrinkage stress is at an appropriate level, the film does not break at the corners when encapsulating, and hermetic encapsulation can be performed to prevent the intrusion of dust from the outside.

In addition, the maximum thermal shrinkage stress is a value obtained by measurement at 120°C in accordance with ASTM D-2838.

Furthermore, the thickness of the polyolefin resin film is preferably 10 μm or more, more preferably 200 μm or less. Further preferably, the thickness is 20 μm or more, most preferably 180 μm or less. When the thickness is within the range, the film has a proper body, and thus the work of wrapping packaged products can be performed smartly, easily and efficiently. Also, heat sealing can be performed with high welding strength, and the film has sufficient breaking strength to resist impact during transportation or handling.

As the fixing member employed in the present invention, any long string or belt can be used. For example, a strap made of polypropylene is preferred.

The buffer bodies of the present invention are used in groups of four. The shapes of the four buffer bodies may be identical or different from each other. For example, in the case of packaging a large-sized glass substrate, a larger and thicker buffer body can be used as a lower buffer body in order to bear the weight of the glass substrate.

In addition, in addition to using the buffer body of the present invention in groups of four as described above, the buffer body of the present invention can also be used in the following manner. That is, two buffer bodies of the present invention can be fixed on the bottom in a plastic container or a plastic corrugated box with an upper opening along opposite directions with a retainer to prevent the buffer bodies from moving, and insert the glass substrate from the upper opening to to fix. If desired, the upper opening can be closed with a cover to prevent the ingress of dust. This can be used for storage of a glass substrate. In this case, the container can also be used for transport when the cushioning body or plastic foam sheet according to the invention is fastened to said lid.

example

Example 1 and Reference Example 1

(Glass base board)

Mother glass for liquid crystal displays

Size: 600mm×720mm

Thickness: 0.7mm

(Foam)

Resin material:

Ethylene-propylene random copolymer with an expansion ratio of 20cm ³ /g; average particle diameter of resin foam particles: 3.6mm

Fusion ratio: 86%

Compression elasticity index: 549N/cm ²

(buffer)

Number of glass substrates to be packed: 26

Dimensions:

Short side: 250mm

Long side: 350mm

Length (at right angles to short side and long side): 300mm

Maximum thickness: 32mm

Base plate insertion slot:

Width: 2.4mm

Depth: 12mm

Spacing: 20mm

The shape of the protrusion:

Has a vertical wall of 6.5mm from the bottom of the substrate insertion groove, and a trapezoidal top with a width of 8mm and a height of 5.5mm in the flat part (shape as shown in Figure 4(c))

(Fixer Guide Slot)

At positions spaced from both sides by 1/4 of the aforementioned length (300 mm) of the buffer body, two 30 mm fixing member guide grooves were formed. The depth of the groove was 1 mm at the end of the L shape, and an arc-shaped slope was formed with a radius of 20 mm, and the depth at the junction between the bottom of the groove and the slope was 4 mm.

(free fall test)

The glass substrates were packaged using four of the above-mentioned buffer bodies as shown in FIG. 2 to prepare a packaged product. In order to evaluate the cushioning properties of the cushioning bodies in the packaged articles, the packaged articles were subjected to a free fall test. In addition, as Reference Example 1, the same test was performed using the same buffer except that the fusion ratio was 65%.

Test conditions:

Drop height: 30cm

The falling surface of the packaged product: the bottom surface of the packaged product only

Number of falls: 3 times

The packaged product of Example 1 did not detach from the glass substrate even after being dropped three times, and maintained the packaged state before the test, and no damage was found. Furthermore, as for the deposition of the dust of the buffer body on the surface of the glass substrate, no dust of a visible size was found at all.

In the packaged product of Reference Example 1, although the glass substrate was not detached, fine chips were generated on the bottom surface at the corners of the glass substrate along the long side direction of the buffer body with the groove. Careful observation of the buffer body and investigation of the cause of the fragmentation revealed that cracks were formed between the foam beads, and it was deduced that the cause was that the glass substrate was embedded in the buffer body due to the impact of the drop. In addition, the movement locus of the foam beads was also found, and thus the buffer of this buffer ratio 1 was found to be inferior in repeated use resistance. That is, since the fusion ratio of the shock absorbers is lower than 70% or less, they necessarily lower the mechanical strength of the shock absorbers, and it is assumed that excessive deformation will occur when subjected to a drop impact.

Example 2 and Comparative Example 1

(Glass base board)

Mother glass for liquid crystal displays

Size: 550mm×650mm

Thickness: 0.7mm

(Foam)

Resin material:

Cross-linked polyethylene with an expansion ratio of 20 cm ³ /g and a resin density of 0.930 g/cm ³

Average particle size of resin foam particles: 2.8mm

Fusion ratio: 98%

Compression elasticity ratio: 412N/cm ³

Compression elasticity index: 41.2

(buffer)

Number of glass substrates to be packed: 12

Dimensions:

Short side: 210mm

Long side: 310mm

Length (at right angles to short side and long side): 240mm

Maximum thickness: 23mm

Base plate insertion slot:

Width: 1.5mm

Depth: 7mm

Spacing: 20mm

The shape of the protrusion:

Has a vertical wall of 3.5 mm from the bottom of the substrate insertion slot, and a herringbone top with a height of 3.5 mm (shape as shown in Figure 4(b))

(Fixer Guide Slot)

The width of the guide grooves of the two fixing parts is 25mm, at the position of 1/4 of the buffer body length (240mm) away from the two sides. The groove is formed from a position spaced 50 mm from the end of the L-shape toward the corner, and a circular slope with a radius of 10 mm is formed at the corner, and at the junction between the bottom of the groove and the slope The depth is 3mm.

(vibration test)

The glass substrates are packaged by using the above four buffer bodies as shown in FIG. 2, so as to produce a packaged product. To evaluate the ability of the cushioning body to hold the glass substrate, the packaged article was subjected to a vibration test. Vibration testing was performed according to JIS Z0232 by fixing the packaged product to a vibration-applied platform of a vibration tester. As Comparative Example 1, the same test was performed using the same cushioning body except that the depth of the guide groove of the fixing member was 1 mm at all positions.

Test Conditions:

Vibration Direction: Up and Down

Vibration waveform: sine wave

Sweep: record sweep (frequency 5 to 100Hz)

Scanning speed: 0.5octave/min

Vibration acceleration: ±0.75G

Vibration time: 30 seconds

After the vibration test was completed, visual observation of the package fixing state of the glass substrate showed that although slight looseness was found between the glass substrate and the buffer body, no glass substrate came out of the substrate insertion groove in Example 2, and, with respect to the buffer body As for the deposition of dust on the surface of the glass substrate, no dust of a visible size was found at all.

With the packaged product of Comparative Example 1, at 8 minutes after the start of the vibration test, the glass substrates were separated from the substrate insertion grooves on the long side sides of the two upper buffers and were in contact with the adjacent glass substrates, so due to the presence of damaged risk and stop testing.

The present invention has been described in detail with reference to specific embodiments, and it will be understood by those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention.

This application is based on Japanese Patent Application No. 396934/2000 filed on November 27, 2000, and the contents thereof are incorporated herein by reference.

Industrial Applicability

In summary, the cushioning body of the present invention prevents the binding force of the fixing member from concentrating on the corners when bundling with the fixing member, and thus the fixing member is well pressed against the glass substrate even at the end, so as not to The glass substrate is pushed out of the groove, thus exhibiting a good protective effect. In particular, by adjusting the size of the cushioning body and adopting a foam having specific properties as the foam constituting the cushioning body, the work of packing and taking out the glass substrate can be easily performed, and it is suitable for automatic modification work. In addition, the buffer body is excellent in dust-proof performance and durability, is suitable for handling in a clean room, and can be used repeatedly. Therefore, in the packaged product packaging a plurality of glass substrates of the present invention, the packaged glass substrates can be safely protected from vibration shock or drop shock during transportation, and conspicuous defective individuals can be pressed out.

Claims (10)

1. buffer body that is used for glass substrate, comprise polyolefin pearl foams, and have the roughly L shaped cross section consistent with the shape in glass substrate bight, go up along a plurality of substrate insertion grooves of formation on the surface within it, in order to the fixing both sides that form the glass substrate in bight, and on its outer surface along at least one connecting element guide groove of formation, wherein, thickness based on the buffer body of the bottom of connecting element guide groove reduces to central part gradually from L shaped two ends, and, with the rectangular direction of substrate insertion groove, buffer body has cutting.

2. the buffer body that is used for glass substrate as claimed in claim 1, wherein, the bottom of connecting element guide groove tilts at the place, bight.

3. buffer body that is used for glass substrate, comprise polyolefin pearl foams, and have the roughly L shaped cross section consistent with the shape in glass substrate bight, go up along a plurality of substrate insertion grooves of formation on the surface within it, in order to the fixing both sides that form the glass substrate in bight, wherein, the thickness of buffer body reduces to central part gradually from L shaped two ends, and, with the rectangular direction of substrate insertion groove, buffer body has cutting.

4. buffer body that is used for glass substrate, comprise polyolefin pearl foams, and have the roughly L shaped cross section consistent with the shape in glass substrate bight, go up along a plurality of substrate insertion grooves of formation on the surface within it, in order to the fixing both sides that form the glass substrate in bight, wherein form protrusion in the outside at L shaped two ends.

5. the buffer body that is used for glass substrate as claimed in claim 4, wherein, an external angle of buffer body is a bevelled.

6. as the described buffer body that is used for glass substrate of one of claim 1 to 5, wherein, in the inboard of buffer body along and the rectangular direction of substrate insertion groove form cutting.

7. as any one described buffer body that is used for glass substrate in the claim 1 to 5, wherein, this buffer body has 10 to 60mm maximum ga(u)ge, based on short brink, the ratio that forms L shaped both sides is 1.0 to 3.0, and the substrate insertion groove has 1.0 to 4.0 times the width that is equivalent to thickness of glass substrate, and the degree of depth is 3 to 15mm, and separation is 6 to 100mm.

8. as any one described buffer body that is used for glass substrate of claim 1 to 5, wherein, polyolefin pearl foams comprise that average particle size particle size is 1.5 to 5.0mm particle, and have 70% or bigger fusion ratio, 3.9 elasticity of compression index, and 60% or bigger answer ratio to 490.

9. packing articles comprises:

A plurality of glass substrates;

The buffer body that is used for glass substrate as claimed in claim 1 is inserted in the substrate insertion groove by four bights with glass substrate, and under the state that glass substrate is arranged in parallel with predetermined spacing, this buffer body is fixed a plurality of glass substrates; And

Long connecting element twines so that tie up along the connecting element guide groove of buffer body.

10. packing articles comprises:

A plurality of glass substrates;

As claim 3 or the 4 described buffer bodies that are used for glass substrate, be inserted in the substrate insertion groove by bight glass substrate, under the state that glass substrate is arranged in parallel with predetermined spacing, this buffer body is fixed a plurality of glass substrates; And

Long connecting element twines so that tie up along the connecting element guide groove of buffer body.

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