JPH052126B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for manufacturing a liquid crystal display element, in particular, a method for manufacturing a liquid crystal display element, in which a base material for a liquid crystal display element is fixed on an endless belt made of a slightly tacky adhesive layer, and The present invention relates to a method of manufacturing a liquid crystal display element that utilizes the ease of peeling of the liquid crystal display element at a bent portion of a belt near a pulley.

(Prior Art) Liquid crystal display elements, which are widely used as display elements for small electronic calculators, electronic watches, etc., are usually manufactured as follows. An electrode pattern corresponding to a desired display pattern is formed on a pair of base materials, and then the base materials are subjected to surface treatment so as to have liquid crystal molecular orientation. Then, after a sealing material for sealing the periphery is formed on at least one of the base materials by a method such as applying, this base material is assembled. Next, cutting is performed in appropriate device units, and liquid crystal is injected between the base materials and sealed with the above-mentioned sealing material to obtain a desired liquid crystal display device.

A pair of base materials used for liquid crystal display elements has a thickness of 0.05~
Since they are made of thin plates such as 0.3 mm thick glass plates and 0.025 mm to 0.05 mm thick polyethylene terephthalate plates, handling during the manufacturing process of liquid crystal display elements is extremely difficult. Although liquid crystal display elements are manufactured on an auxiliary substrate made of glass or metal, the thin substrate slides on this auxiliary substrate and sometimes breaks due to impact. As a result, defective products frequently occur and continuous production is not possible.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems, and its purpose is to provide a method for manufacturing liquid crystal display elements quickly and with a low defect rate. be. Another object of the present invention is to provide a method for continuously manufacturing liquid crystal display elements.

(Means for Solving the Problems) The present invention provides that when a substrate for a liquid crystal display element is adhered to an auxiliary substrate using an adhesive, surface treatment of the base material becomes easier, and as a result, manufacturing of the liquid crystal display element is facilitated. can be carried out quickly without producing defective products; and when the auxiliary substrate is composed of an endless belt made of a slightly adhesive adhesive layer, the liquid crystal display element manufactured on this endless belt can be This was completed based on the inventor's knowledge that it is easily peeled off at bent portions. Therefore, the method for manufacturing a liquid crystal display element of the present invention includes surface-treating a pair of base materials provided with an electrode pattern corresponding to a desired display pattern, and providing a sealing material around at least one of the base materials. A method for manufacturing a liquid crystal display element by assembling the base materials and injecting liquid crystal between the base materials, the method comprising forming one of the pair of base materials for the liquid crystal display element at least on the surface with a slight adhesive layer. and adhering it to an endless belt wound around a pair of pulleys, producing a liquid crystal display element, and after producing the liquid crystal display element, bending portions of the endless belt near the pulleys that are running on the endless belt. The method includes peeling off the liquid crystal display element from the endless belt, thereby achieving the above object.

As the slightly adhesive adhesive used in the present invention,
Examples include microspherical adhesives and adhesives containing microcapsules.

For example, the particle size of the microspherical adhesive is 7 to 100μ.
Adhesive microparticles are preferably in the range of m;
Any conventionally known fine particles can be used, for example, primary or secondary fine particles having 4 to 10 carbon atoms.
Examples include suspension adhesives made of copolymers of acrylic acid esters of alcohols and 2-acrylamido-2-methylpropanesulfonic acid and/or 2-acrylamido-2-methylpropanesulfonic acid salts. Acrylic acid esters are esters of acrylic acid and primary or secondary alcohols having 4 to 10 carbon atoms, such as n-butyl acrylate, isobutyl acrylate, isoamyl acrylate, and 2-ethylhexyl acrylate. Also, 2-acrylamide-2-
What is methylpropanesulfonic acid? It is represented by the following structural formula, and its salts include sodium salt, potassium salt, and ammonium salt. 2-acrylamido-2methylpropanesulfonic acid and its salts may be used alone or in combination. 2-acrylamide-
In the case of 2-methylpropanesulfonate, different types of salts such as sodium salt and potassium salt may be used in combination. When the proportion of 2-acrylamide-2methylpropanesulfonic acid or its salt in the copolymer increases, the adhesive force decreases, and when the proportion thereof decreases, the particle size of the adhesive microparticles tends to become irregular. Acrylic acid ester 70~
It is preferable to use 0.5 to 10 parts by weight based on 99.5 parts by weight. For the purpose of increasing the cohesive force, monomers such as methyl acrylate, ethyl acrylate, acrylonitrile, and vinyl acetate may be used within a range of 20% by weight based on the total monomer ratio.
Moreover, it is also possible to mix various tackifiers, ordinary solution-type adhesives, etc. into the adhesive composition as necessary.

As a method for obtaining such a suspension adhesive composition, a conventionally known suspension polymerization method may be used. Anionic surfactants can be suitably used as the dispersant. This suspension-based adhesive composition has uniform adhesive microparticle diameters within a certain range, improves coating performance in roll coating on endless belts, has an appropriate coating thickness, and maintains coating film quality. It has the advantage that an excellent adhesive layer can be obtained.

The adhesive containing the microcapsules as a slightly adhesive adhesive that can be used in the present invention is, for example, a composition comprising an adhesive and thermally expandable microcapsules. The adhesives used here are conventionally known, such as solution type,
Adhesives include acrylic, rubber, urethane, and silicone adhesives such as emulsion and hot melt types. Thermally expandable microcapsules are microspheres at room temperature, expand upon heating, and then maintain their expanded shape even after cooling. It is preferable that a low-boiling hydrocarbon such as propane, butane, pentane, hexane, etc. is contained in the resin shell wall of the adhesive such as a combination. For example, Matsumoto Microsphere-F-30, F-50, F manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd.
−60, etc. can be given. By blending and mixing the above adhesive and thermally expandable microcapsules, a desired slightly adhesive adhesive can be obtained. The amount of heat-expandable microcapsules to be added is appropriately determined depending on the foamability of the heat-expandable microcapsules and the adhesive strength of the resulting slightly sticky adhesive, but is generally 0.5 to 0.5 to 100% of the adhesive (solid content). 20 parts by weight is added. The slightly sticky adhesive containing microcapsules thus obtained is applied directly to the endless belt. If this slightly sticky adhesive is a solution type or emulsion type, it can be heated and foamed after or during evaporation of the solvent or water, or if it is a hot melt type, it can be heated and applied to an endless belt. It may be heated and foamed during coating or after coating. As conditions for heating and foaming the expandable microcapsules, heating at 100 to 160° C. for 1 to 5 minutes is generally employed.

The endless belt used in the present invention does not need to be special, and can be formed by winding a normal conveying flat belt, toothed belt, etc. around a pair of pulleys. Such belts are generally made of rubber materials such as chloroprene rubber, styrene-butadiene rubber, nitrile, and butadiene rubber, which have high flexibility and elasticity. A core wire made of glass fiber or the like is embedded in the rubber material to maintain the rigidity of the belt, and the surface of the rubber material is covered with stretchable canvas or non-stretchable canvas such as nylon fiber or polyester fiber as a reinforcing member. There is.

The slightly sticky adhesive is applied to at least the surface side of this endless belt, or the single-sided or double-sided adhesive tape having the slightly sticky adhesive layer is applied to the endless belt so that the slightly sticky adhesive layer is on the surface. It is pasted and used as a fixing member for a substrate for a liquid crystal display element. For example, as shown in the figure,
A slightly sticky adhesive layer 21 is formed on at least the surface side of the endless belt 2 wound around a pair of pulleys (a driving pulley and a driven pulley) 1. A liquid crystal display element base material 31 is adhered and fixed onto this adhesive layer 21. Then, a step of forming a desired electrode pattern, a surface treatment step of the base material 31, and a step of forming a desired electrode pattern.
The liquid crystal display element 3 is manufactured according to a normal liquid crystal display element manufacturing process including a process of arranging the sealing material 32 around the periphery, an assembly process of the base material 31, a process of injecting the liquid crystal 33 between the base materials 31, and the like. Base material 3 throughout each process
1 is fixed on the endless belt 2 by the adhesive layer 21, so that it does not shift or come apart on the endless belt 2, and therefore there is no accident of damage. Next, the drive pulley 1 is driven by a pulley drive means (not shown) to cause the endless belt 2 to travel. The liquid crystal display element 3 runs together with the endless belt 2. As the belt portion 20 to which the liquid crystal display element 3 is attached approaches the belt bent portion 22 near the pulley 1, it curves along the pulley 1, so that the bottom surface of the flat liquid crystal display element is bent away from the belt portion 20. It is gradually forcibly removed. Since the adhesive layer 21 that adheres the liquid crystal display element 3 to the belt portion 20 is made of a slightly adhesive adhesive, there is no risk that the liquid crystal display element 3 will be damaged by this forced peeling. Then, when the liquid crystal display element 3 comes to the belt bent portion 22, the bonding area between the two becomes extremely small. At this time, the liquid crystal display element 3 is separated from the endless belt 2. In this way, the manufactured liquid crystal display elements 3 are continuously collected without damage. The adhesive force of the slightly adhesive adhesive layer 21 at the belt bending part 22 and its vicinity is usually 30
It is preferable that it is ~80g/15mm width. The endless belt 2 having the slightly sticky adhesive layer 21 may be one in which an adhesive tape having the slightly sticky adhesive layer 21 is attached to the endless belt 2, or the endless belt 2 itself may have the slightly sticky adhesive layer 2.
1 can still achieve the object of the present invention.

In addition, an adhesive made of silane resin is used as the slightly adhesive adhesive layer, and the adhesive layer is heated near the belt bending part to facilitate natural peeling of the liquid crystal display element at the belt bending part and its vicinity. It is also recommended that This adhesive also has an adhesive strength of 30 to 80g/15mm.
It is preferably width. Such adhesives are
For example, it consists of a polyether having at least one reactive silane group in its molecule, a tackifier, and a crosslinking catalyst. Polyether has at least one silane group represented by the following formula in its molecule.

Here, n is an integer of 0 to 2, R is a hydrocarbon group, and X
is a hydrolyzable group, such as an alkoxy group.

The main chain constituting polyether has the formula (-R'-O-)
It has a repeating unit represented by R' is an alkylene group, especially an ethylene group, a propylene group, a butylene group, an isopropylene group, etc. having 1 to 4 carbon atoms.
An alkylene group is preferred. This polyether has two silane groups at both ends of the main chain, and has a molecular weight of
It is preferably 300 to 15000, more preferably
It is 1000-10000. Further, the tackifier does not need to be particularly special, and there are no particular limitations as long as it can be used in adhesives. Among these, those having good compatibility with the above-mentioned polyethers are preferred, such as terpene phenol resins, synthetic terpene resins, partially hydrogenated rosin glycerin esters, fully hydrogenated rosin glycerin esters, and coumaron resins. The amount of tackifier added may be appropriately determined depending on the required quality of the adhesive layer to be finally obtained, but as the amount added increases, the adhesive strength increases, so generally, 100 parts by weight of polyether is added.
It is preferable that it is not more than parts by weight.

The crosslinking catalyst constituting the adhesive is for crosslinking the reactive silane groups of polyether, and includes, for example, a silanol condensation catalyst. Examples of the silanol condensation catalyst include organotin compounds such as dibutyltin dilaurate, organotitanium compounds such as tetraisopropyl titanate, tetrabutyl titanate, and diisopropoxytitanium bisacetylacetate, amines such as laurylamine and ethanolamine, and tin octylate. Examples include organic acid metal salts such as lead octylate and iron naphthenate. The amount of crosslinking catalyst added is preferably 0.1 to 10 parts by weight per 100 parts by weight of polyether.

(Example) The present invention will be described below with reference to examples.

Example 1 200 parts by weight of ion-exchanged water, butyl acrylate
90 parts by weight, 6 parts by weight of 2-ethylhexyl acrylate, 4.5 parts by weight of sodium salt of 2-acrylamido-2methylpropanesulfonic acid, 0.25 parts by weight of benzoyl peroxide, and 4 parts by weight of anionic surfactant (30% solids solution). A part was polymerized in a nitrogen stream to prepare an aqueous dispersion of sticky microparticles. The obtained polymer was left to stand for 72 hours to completely precipitate the sticky microparticles. After drying the precipitate, it was dispersed in toluene to obtain a 7% by weight toluene dispersion. Next, this dispersion was applied using a reverse roll coater, and the clearance of the coater was adjusted.
It was maintained at 150μ and was continuously coated onto a belt with a coating width of 50cm. After winding the belt with the microspherical adhesive layer formed in this way around a pulley to form an endless belt, a substrate for a liquid crystal display element made of a glass plate with a thickness of 0.05 mm is attached to this, and a liquid crystal display element is formed. was produced by a conventional method. This thin base material was fixed at a predetermined position on the endless belt, and was not damaged due to displacement or detachment during the manufacturing process of the liquid crystal display element. After manufacturing the liquid crystal display element, the endless belt was run, and when the liquid crystal display element came to a bend in the belt, it was pulled away from the belt. The liquid crystal display element was easily separated and no damage was observed.

Example 2 15 parts by weight of an isocyanate curing agent (Coronate L, manufactured by Nippon Polyurethane Co., Ltd.) was added to a solution of copolymerizing 97 parts by weight of butyl acrylate and 3 parts by weight of acrylic powder in 150 parts by weight of ethyl acetate, and the mixture was mixed. An acrylic adhesive solution was obtained. Thermal expansion microcapsules (manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., Matsumoto Microsphere F) were added to the obtained acrylic adhesive solution.
-30) was added and mixed. The resulting adhesive composition was applied to the belt and dried at 100°C for 5 minutes to coat the belt surface with 80μ microcapsules.
A slightly adhesive adhesive layer with a thickness of m was formed. Using this belt, an endless belt was formed in the same manner as in Example 1, and liquid crystal display elements were manufactured. As a result, there was no damage to the base material, and the desired liquid crystal display elements were quickly and continuously obtained without damage. It was done.

Example 3 Silane-modified polyether (manufactured by Kanebuchi Chemical Co., Ltd., MS
Polymer 300) 100 parts by weight, 50 parts by weight of terpene phenol resin 60% toluene solution (Yasu Oil Co., Ltd., YS Polyster T-115) and 3 parts by weight of dibutyltin dilaurate were stirred and mixed to obtain an adhesive solution. The obtained adhesive solution was applied to one side of the belt and dried at 100° C. for 10 minutes to obtain a belt with a silane adhesive layer having a thickness of 30 μm. A glass plate was attached to the obtained belt, and the adhesive strength of the obtained belt (according to ASTMD-1000) was measured at 23°C, and it was found to be 50 g/15 mm width.

A belt provided with a silane adhesive layer having such adhesive strength was formed into an endless belt in the same manner as in Example 1. When a liquid crystal display element was manufactured according to a conventional method, the base material was fixed in a predetermined position and was not damaged. After manufacturing the liquid crystal display element, an endless belt was run, and the liquid crystal display element was separated from the belt at the belt bend. Since the adhesive strength of the adhesive layer at the belt bend and its vicinity was significantly reduced, the liquid crystal display element could be easily separated and no damage was observed.

(Effects of the Invention) As described above, in the present invention, since the liquid crystal display element is manufactured on the endless belt having the slightly adhesive adhesive layer, the substrate for the liquid crystal display element is placed at a predetermined position on the endless belt. It is fixed and there is no damage caused by shifting or separating. Moreover, after manufacturing, the liquid crystal display element can be easily separated from the belt without damage by utilizing the partial natural peeling of the liquid crystal display element at the bent portion of the belt. According to the method of the present invention, continuous production of liquid crystal display elements is possible.

[Brief explanation of the drawing]

The figure is an explanatory diagram illustrating the manufacturing method of the present invention. 1...Pulley, 2...Endless belt, 3...
...Liquid crystal display element, 20...Belt portion to which liquid crystal display element is attached, 21...Slightly sticky adhesive layer, 22
...Belt bent portion, 31...Base material for liquid crystal display element, 32...Sealing material, 33...Liquid crystal.

Claims (1)

[Claims] 1. A pair of base materials provided with an electrode pattern corresponding to a desired display pattern are subjected to surface treatment, a sealing material is provided around at least one of the base materials, and the base materials are assembled; A method for manufacturing a liquid crystal display element by injecting liquid crystal between the base materials, the method comprising: one of the pair of base materials for liquid crystal display elements having at least a surface formed with a slightly sticky adhesive layer and a pair of pulleys; pasting it on a wound endless belt, producing a liquid crystal display element, and after producing the liquid crystal display element, attaching the liquid crystal display element to a bent part near a pulley of the endless belt running on the endless belt; A method for manufacturing a liquid crystal display element, comprising: peeling off from an endless belt. 2. The manufacturing method according to claim 1, wherein the slightly adhesive adhesive layer is a microspherical adhesive made of adhesive microparticles. 3. The manufacturing method according to claim 1, wherein the weak adhesive layer is an adhesive composition comprising an adhesive and thermally expandable microcapsules. 4. The manufacturing method according to claim 3, wherein the microcapsules contain a low-boiling hydrocarbon within a thermoplastic resin shell wall. 5 The slightly adhesive adhesive contains at least 1 in the molecule.
Claim 1 comprising a polyether having reactive silane groups, a tackifier, and a crosslinking catalyst.
The manufacturing method described in section.