JPH01218831A - Formation of three-dimensional shape - Google Patents

Abstract

PURPOSE:To improve workability, to enhance the accuracy of an obtained object having a three-dimensional shape and to simplify an apparatus, by repeating a process for selectively irradiating a photo-setting resin sheet and laminating a new photo-setting resin sheet to selectively irradiate the same with light. CONSTITUTION:A photo-setting resin sheet 1 cured by the irradiation with light is laid on the planar part 2 of the irradiation part of a light irradiation apparatus and selectively irradiated with light having energy necessary for curing corresponding to a three-dimensional shape to form a cured part 11 and the irradiation quantity of light at this time is set so as to obtain the continuous cured part 11 reaching the upper and lower surfaces of the sheet by the irradiation with light. Next, a new photo-setting resin sheet 1' is laminated to the sheet 1 and subsequently irradiated with light having energy necessary for curing selectively in the same way corresponding to the three-dimensional shape to form a cured part 11'. This process is repeated predetermined times to form a three-dimensional object having a desired shape and, subsequently, development is performed in order to remove an uncured part 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method of forming an arbitrary three-dimensional shape using a light and photocurable resin sheet.

[Conventional technology]

In recent years, Japanese Patent Application Laid-Open No. 60-247515 has proposed a method of forming a desired three-dimensional object by selectively supplying energy necessary for curing to a photocurable liquid material.

A similar method or improved technique is described in U.S. Patent No. 4.5.
Specification No. 75,330 (corresponding Japanese Patent Application Publication; JP-A-62-35966), JP-A-62-1014
It is also disclosed in Publication No. 08 and the like.

A typical example of this three-dimensional modeling method is to selectively irradiate the liquid surface of a photocurable resin in a container with, for example, an ultraviolet laser to obtain a cured layer in a desired pattern. , then supplying one layer of photocurable resin onto the cured layer,
Next, by repeating the lamination operation to selectively irradiate light and obtain a continuous cured layer with the above-mentioned cured layer in the same manner as above,
This is a method to finally obtain a desired three-dimensional object.

This three-dimensional modeling method is attracting attention because even when the shape of the object to be produced is complex, it is possible to easily obtain the desired object in a short time.

[Problem that the invention seeks to solve]

However, the molecular weight of the photocurable resin used in the method for forming three-dimensional objects cannot be increased;
Therefore, there is a drawback that reaction shrinkage is large during photocuring, and dimensional errors after modeling reach several percent, making it difficult to produce precise three-dimensional objects.

Furthermore, in order to achieve a uniform layer thickness with a smooth surface, the equipment needs to be large and the thixotropy of the cured and uncured parts is different, so liquid photocurable resin must be laminated in thin layers with good reproducibility. It is difficult to achieve this, and the dimensional accuracy of the three-dimensional objects obtained varies.

The present invention has been made against the background of the above-mentioned problems of the prior art, and aims to provide a method for forming a three-dimensional shape with good workability, extremely high precision of the three-dimensional shape obtained, and a simple manufacturing device. purpose.

[Means for solving problems]

The present invention (a) selectively irradiates a photocurable resin sheet that is cured by light irradiation with light having the energy necessary for curing, and (b) then creates a new photocurable resin on the sheet after light irradiation. A step of laminating resin sheets, selectively irradiating the sheets with light having the energy necessary for curing, (c) further repeating the step (b) a predetermined number of times, and (d) then removing the remaining portion of the photocurable resin. The present invention provides a three-dimensional shape forming method that includes a step of removing a hardened portion.

In the present invention, first, (a) a photocurable resin sheet that is cured by light irradiation is selectively irradiated with light having energy necessary for curing so as to obtain a desired shape.

Here, the light used in the present invention differs depending on the photocurable resin described below, but usually various types of light such as visible light and ultraviolet light can be used, and these lights may be ordinary light, but By increasing the energy level by using a laser beam, the time required to form a three-dimensional shape can be shortened, and the formation precision can be improved by utilizing the excellent light focusing ability.

Furthermore, the photocurable resin constituting the photocurable resin sheet that is cured by light irradiation (hereinafter simply referred to as "f photocurable resin sheet") used in the present invention is a solid resin that is cured by light irradiation. Although not particularly limited, for example, a solid prepared by adding a polymerization initiator, thickener, etc. that generates radicals, nitrene, etc. when exposed to light to the compounds shown in the following ■~O, and during work and storage. Mention may be made of semi-solid resins having a pour point above the temperature of

■Polyvinyl alcohol, polybutyral, and polyacetal having two or more cinnamic acid groups in one molecule.

■It has two or more acrylic double bonds in one molecule, and the polymer skeleton is polyester, polyurethane, epoxy,
A polymer consisting of at least one selected from polyether, polycarbonate, polyamide, etc., and a mixture of these polymers and a photocurable monomer.

■Polyester resin containing photocurable unsaturated double bonds such as maleic acid and fumaric acid in the molecule.

For example, saturated polybasic acids such as phthalic acid, isophthalic acid, succinic acid, adipic acid, and sebacic acid, ethylene glycol, diethylene glycol, glycerin, trimethylolpropane, 1.2-7" propylene glycol,
3-butanediol, dipropylene glycol, 1.4
- A polybasic acid that is a raw material for polyesters obtained by ester bonding with polyhydric alcohols such as butanediol, 1,6-hexanediol, pentaerythritol, sorbitol, glycerin, neopentyl glycol, and 1,4-cyclohexanediol. obtained by replacing part with an unsaturated polybasic acid such as maleic acid,
A photocurable unsaturated polyester resin with unsaturated double bonds.

■Two photocurable functional groups are added to water or hot water-soluble polymers such as polyvinyl alcohol and polyvinylpyrrolidone.
A photocurable resin made by mixing monomers having more than 100% monomers, such as polyfunctional (meth)acrylic acid ester, acrylamide, divinylbenzene, etc.

■ Polymers such as polyvinyl alcohol that are soluble in water or hot water that have been given photocurability, and mixtures of these and photocurable monomers.

■ Monomers with two or more photocurable functional groups, such as polyfunctional (meth)acrylic esters and acrylamide, in polymers soluble in alkaline aqueous solutions such as cellulose acetate succinate, polyvinyl pyridine, and sulfonic acid group-containing polyamides. A photocurable resin made by mixing divinylbenzene, divinylbenzene, etc.

■Polymer cells that have been given photocurability to polymers soluble in alkaline aqueous solutions such as polyvinylpyridine and sulfonic acid group-containing polyamides, and mixtures of these and photocurable monomers.

■ A polyfunctional (meth)acrylate ester having two or more photocurable functional groups in a polymer soluble in a weakly acidic aqueous solution such as polyamide containing a quaternary ammonium salt,
A photocurable resin made by mixing acrylamide, divinylbenzene, etc.

(2) Polymers obtained by imparting photocurability to monomers soluble in weakly acidic aqueous solutions, such as polyamides containing quaternary ammonium salts, and mixtures of these and photocurable polymers.

[Phase] Polymers obtained by imparting photocurability to cellulose polymers such as nitrified cotton, cellulose acetobutyrate, ethylene cellulose, butyl cellulose, and acetyl cellulose, and mixtures of these and photocurable polymers.

(2) Polymers obtained by imparting photocurability to polyfunctional polyesters such as polycaprolactone, and mixtures of these and photocurable polymers.

0 Vinyl chloride-vinyl acetate-vinyl alcohol copolymer, vinyl chloride-vinyl alcohol copolymer, vinyl chloride-vinyl acetate-maleic acid copolymer, vinyl chloride-
A polymer obtained by imparting photocurability to a vinyl propionate-vinyl alcohol copolymer, etc., and a mixture of these and a photocurable monomer.

(2) Polymers obtained by imparting photocurability to butadiene polymers, styrene-butadiene copolymers, acrylonitrile-butadiene copolymers, etc. having hydroxyl or carboxyl groups at the terminals, and mixtures of these and photocurable monomers.

(2) A polymer obtained by adding α,β-ethylenically unsaturated monocarboxylic acid to an epoxy compound of a diene polymer, and a mixture of these and a photocurable monomer.

[Phase] A polymer obtained by adding α,β-ethylenically unsaturated monocarboxylic acid to the epoxy group of a polymer or copolymer of glycidyl acrylate or glycidyl methacrylate, and a mixture of these and a photocurable monomer.

[Phase] Conjugated diolefin hydrocarbon (A) and α.

β-ethylenically unsaturated carboxylic acid (B) is an essential component, and a monoolefinically unsaturated compound (C) is added to this,
(A); 10 to 95 mol%, (B); 5 to 90 mol%,
(C); A mixture of a copolymer and a photopolymerizable monomer in a proportion of 0 to 85 mol % (Japanese Patent Laid-Open No. 134655/1983).

A resin composition containing a cyclized product of an O-butadiene polymer or a butadiene copolymer as a main component and blending this with a photosensitive crosslinking agent (Japanese Patent Publication No. 59-42999).

Next, specific examples of methods for imparting photocurability to the compounds (1) to (2) described above are shown in (I) to (I[[) below.

(I) reacting the isocyanate group of one or more molecules of a polyisocyanate compound in one molecule of the thermoplastic polymer or these prepolymers having a hydroxyl group and/or a primary or secondary amino group in the molecule; Next, it is reacted with one or more molecules of a monomer having a functional group that reacts with an isocyanate group and a photocurable unsaturated double bond. Monomers having a functional group that reacts with an isocyanate group and a photocurable unsaturated double bond include hydroxyl groups such as 2-hydroxyethyl ester, 2-hydroxypropyl ester, or 2-hydroxyoctyl ester of acrylic acid or methacrylic acid. Ester monomers having an ester; monomers having an active hydrogen that reacts with isocyanate groups such as acrylamide, methacrylamide, and N-methylolacrylamide and containing acrylic and double bonds; allyl alcohol, maleic acid polyhydric alcohol Examples include monomers containing unsaturated double bonds that have active hydrogen that reacts with isocyanate groups and have photocurability, such as ester compounds and mono- or diglycerides of long-chain fatty acids that have unsaturated double bonds. can.

(II) The above-mentioned thermoplastic polymer having a hydroxyl group and/or a primary or secondary amino group in the molecule, or having one or more photocurable unsaturated double bonds in one molecule of these prepolymers. Ester double bonds are introduced by reacting acids or acid halides. Examples of the acid or acid halide having a photocurable double bond include acrylic acid, methacrylic acid, methacrylic acid chloride, acrylic acid chloride, acrylic acid bromide, and methacrylic acid bromide.

(I react with one or more molecules of mer. Monomers having photocurable unsaturated double bonds that react with carboxyl groups include glycidyl acrylate,
Examples include glycidyl methacrylate.

Two or more of these photocurable resins can be used in combination.

The thickness of the photocurable resin sheet used in the present invention is usually 10 to 100 μm, preferably 20 to 50 μm.
If the thickness is less than 10 μm, the sheet strength is weak, resulting in poor operability, and it is also too thin, which may have an adverse effect on the photocurable resin sheets that have been laminated several times during light irradiation.
Furthermore, it takes a long time to form a three-dimensional shape;
If it exceeds 100%, it will be too thick and it will be difficult for the photocuring reaction to occur sufficiently.
Furthermore, it is difficult to obtain smoothness on the surface of the finished three-dimensional molded product, and it is difficult to maintain the accuracy of the surface shape.

In addition, the photocurable resin sheet used in the present invention may be used as it is, but it is usually a polyester film such as a polyethylene terephthalate film, a cellulose acetate film, a polyvinyl chloride film, a polystyrene film, or a polycarbonate film.・A laminate sheet is used in which a film-like photocurable resin is laminated onto a base paper such as polyfluoroethylene film, silicone resin film, linter paper, or kraft paper.

The method for producing the laminated paper includes, for example, stacking the base paper and the above-mentioned photocurable resin and pressing them with a roller, dissolving the above-mentioned photocurable resin in a low boiling point solvent,
Examples of methods include applying this onto a base paper and then removing the solvent, but the method is not limited to these methods.

In step (a) of the present invention, the laminate sheet is pulled out from the laminate sheet roll onto the flat surface of the irradiation area, for example, with the base paper facing upward and the photocurable resin sheet facing downward. After that, the base paper is pressed from above with a roller or the like to make it adhere to a flat surface, the base paper is peeled off, and then light is selectively irradiated so as to form a predetermined shape.

After the above step (a) is completed, next (b) a new photocurable resin sheet is laminated on the light irradiated photocurable resin sheet in the same manner as in the above step (a), and this new A photocurable resin sheet is selectively irradiated with light having energy necessary for curing so as to obtain a desired shape. In this case as well, the laminate sheet described above is usually used.

Furthermore, in the present invention, a desired three-dimensional shape is formed by repeating the (c) step (b) a predetermined number of times.

However, if the base paper forming the laminate sheet is one that transmits the light for curing the photocurable resin sheet, the base paper may be peeled off in each of the above steps after irradiation with light. .

In addition, when laminating the photocurable resin sheets, in order to improve adhesion, pressure may be applied using a pressure roller as explained in step (a) above, or a heating roller may be used at this time. Although it is preferable to heat using heating means such as
In the process, a photocurable liquid substance is applied to the laminated surface of the photocurable resin sheets, and the sheets are bonded together at the same time as light irradiation, which eliminates peeling between the photocurable resin sheets.
This is desirable because a solid three-dimensional object can be obtained.

Such photocurable liquid substances include, for example, polyurethane (meth)acrylate synthesized from polyhydric alcohol, polyisocyanate, and hydroxyl group-containing (meth)acrylate; or glycidyl ether synthesized from polyhydric alcohol and epichlorohydrin. Examples include epoxy (meth)acrylates obtained by reacting hydroxyl group-containing (meth)acrylates.

Examples of polyhydric alcohols used in the synthesis of these photocurable liquid substances include polyether diol, polyester diol, polycarbonate diol, and polycaprolactone diol.

Among these, polyether diols include, for example, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and further include liquid polybutadiene having two hydroxyl groups in one molecule or a hydrogenated product of this compound.

Examples of polyester diols include polyhydric diols such as ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, tetramethylene glycol, polytetramethylene glycol, 1,6-hexanediol, neopentyl glycol, and 1,4-cyclohexane dimetatool. alcohol and phthalate,
Isophthalic acid, terephthalic acid, maleic acid, fumaric acid,
Examples include polyester diols obtained by reacting with polybasic acids such as adipic acid and sebacic acid.

Polycarbonate diols include DN-980, DN-981, and DN-982 manufactured by Nippon Polyurethane ■.
, DN-983; PC-8000 manufactured by PPG Corporation in the United States.

Examples of polycaprolactone diol include ε-caprolactone, ethylene glycol, polyethylene glycol, polypropylene glycol, tetramethylene glycol, polytetramethylene glycol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexane dimetatool, 1 .2 such as 4-butanediol
Examples include polycaprolactone diol obtained by reacting a polycaprolactone diol with a polyvalent diol.

In addition, the polyisocyanates used in the synthesis of these photocurable liquid substances include 2,4-toluene diisocyanate, 2,6-)toluene diisocyanate, and 1,3-toluene diisocyanate.
-xylene diisocyanate, 1.4-xylene diisocyanate, 1. 5-naphthalene diisocyanate,
0-phenylene diisocyanate, p-phenylene diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 3,3'-dimethylphenylene diisocyanate, 4,4'-biphenylene diisocyanate, Examples include hexamethylene diisocyanate, isophorone diisocyanate, methylene bis(4-cyclohexyl isocyanate), and the like.

Furthermore, examples of hydroxyl group-containing (meth)acrylates used in the synthesis of these photocurable liquid substances include, for example, 2-
Hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxyoctyl (meth)acrylate, and the following general formula (i)
Or, a compound represented by (ii) can be mentioned.

...... (i) (In the formula, R is a hydrogen atom or a methyl group.)...
... (ii) (In the formula, R is the same as above, and n is an integer of 1 to 5.) The thickness of the photocurable liquid substance applied between the photocurable resin sheets is: Usually 1 to 10 μm, preferably 2
~5 μm.

In addition, in this method of applying the photocurable liquid substance, a roll coater 1 is applied onto a sheet that has already been irradiated with light and selectively photocured.
The coating method may be applied by a brush, spray coating, or the like, or may be applied to the surface of a new photocurable resin sheet by a similar coating method, and the coating method is not limited to these methods.

Further, it is preferable that the photocurable liquid substance used as the adhesive contains a substance capable of attenuating irradiated light (hereinafter referred to as "light attenuating substance").

In this way, when a new photocurable resin sheet is laminated and selectively irradiated with light to cure it, the light will not affect the already photocured sheet laminated adjacent to this sheet. It becomes possible to control the

Note that even if such a light attenuating substance is included in a photocurable resin sheet, the same effect as described above can be expected, but it is necessary to take into account that the degree of curing in the thickness direction of the photocurable resin sheet is uniform. In this case, it is preferable to include it in the above-mentioned photocurable liquid substance.

Such light attenuating substances include, for example, pigments such as titanium dioxide; triphenylmethane dyes such as malachite green, acid magenta, and ethyl violet;
Dyes such as styryl dyes, merocyanine dyes, and oxonol dyes; UV absorbers such as salicylate ultraviolet absorbers, benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, and substituted acrylonitrile ultraviolet absorbers. .

These light attenuating substances can be freely selected depending on the characteristics required for the three-dimensional object produced by the method of the present invention, the type of light used for curing, etc., or two or more types may be used in combination. .

The amount of these light-attenuating substances used varies depending on their light-attenuating ability, etc., but when using the above-mentioned dyes and ultraviolet absorbers, the amount used is usually based on 100 parts by weight of the photocurable liquid material. 0.01 to 10 parts by weight, preferably 0.05 to 5 parts by weight
It is about parts by weight.

Further, when a pigment is used, the amount is usually about 3 to 300 parts by weight, preferably about 5 to 50 parts by weight, based on 100 parts by weight of the photocurable liquid material.

After forming a three-dimensional object as described above, development is performed to remove uncured material.

This development may include development with a dilute alkaline aqueous solution when the above-mentioned photocurable resins of 1 to 2 and [phase] are used. At this time, the alkali used may be a normal alkali, such as sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonia, sodium carbonate, potassium carbonate, lithium carbonate, etc. A concentrated aqueous solution is used as developer.

In addition, when using the photocurable resins of ■ and ■ above,
Can be developed with a weakly acidic aqueous solution.

At this time, the acid used may be any ordinary acid, such as hydrochloric acid,
A low concentration aqueous solution of about 0.1 to 1.0% by weight, such as sulfuric acid, is used as the developing base.

Furthermore, when using photocurable resins other than those mentioned above, alcohols such as methanol, ethanol, isopropyl alcohol, and butyl alcohol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; benzene, toluene, xylene, and cresol; It can be developed using organic solvents such as aromatic hydrocarbons such as .

Hereinafter, the present invention will be explained in more detail using the drawings.

First, in step (a) of the present invention, as shown in FIGS. 1(a) to 1(bl), a photocurable resin sheet l that is hardened by light irradiation is laid on the flat surface 2 of the irradiation part of the light irradiation device. Part 1
(see Fig. 1(a)), then selectively irradiates light having energy necessary for curing corresponding to the three-dimensional shape to be obtained from the light source 3 above the sheet to form a cured portion 11 (see Fig. 1). (see (b)).

The amount of light irradiation at this time is set to the amount that allows a continuous cured portion 11 to be obtained over the upper and lower surfaces of the sheet by light irradiation.

Next, in step (b), a new photocurable resin sheet 1' is added to the sheet 1 as shown in FIGS.
(See Fig. 1 fc)), and then similarly, the light source 3 above the sheet selectively irradiates light having the energy necessary for curing in accordance with the three-dimensional shape to be obtained, to cure the cured portion. 11' (see FIG. 2(d)).

The amount of light irradiation at this time is set to such an amount that a continuous hardened portion 11' extending over the upper and lower surfaces of the sheet is obtained by the light irradiation.

Furthermore, in step (c), a three-dimensional shape having a desired shape is formed by repeating step (b) a predetermined number of times.

Next, in step (d), development is performed to remove the uncured portion 1 in FIG. 1 (cll), for example.

In addition, in the present invention, a method is mainly used in which photocurable resin sheets are laminated and selectively irradiated with light having energy necessary for curing corresponding to the three-dimensional shape to be obtained on the sheet (lamination-light irradiation). However, the method is not limited to this method. For example, first, the cured portion is selectively irradiated with light having the energy necessary for curing in accordance with the three-dimensional shape to be obtained on the photocurable resin sheet. to form,
It is also possible to apply this method to a method of laminating these cured sheets (light irradiation-lamination).

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 1 g of a photocurable resin consisting of 96% by weight of 8-functional polyurethane acrylate having a +11 molecular weight of 20,000 and 4% by weight of benzyl dimethyl ketal as a photopolymerization initiator was heated at 10C.
IIXIO (J) polyethylene terephthalate film was stretched with a roller to a thickness of 50 μm to prepare a laminate sheet.

(2) Next, the obtained laminate sheet was placed on a flat surface with the photocurable resin facing down, and the polyethylene terephthalate film was peeled off to obtain a photocurable resin sheet 1. On this sheet, draw a circle with a diameter of 50' and a wavelength of 325 nm emitted from a light source with an output of 20 mW.
A helium/cadmium laser beam with a focal length of 20
The light was focused and irradiated with a quartz lens of m.

(3) Bifunctional polyurethane acrylate 5 with a molecular weight of 2,000 on the photocurable resin sheet 1 after laser irradiation
0% by weight, 23% by weight of vinylpyrrolidone, 23% by weight of trimethylolpropane triacrylate, 4% by weight of photopolymerization initiator benzyl dimethyl ketal, and 0.6% by weight of ultraviolet absorber 2,4-dihydroxybenzophenone. The resin composition was applied to a thickness of 5 μm.

(4) Next, place the same laminate sheet as above on the photocurable resin sheet 1 with the photocurable resin side facing down,
The polyethylene terephthalate film was peeled off to obtain a photocurable resin sheet 1'.

On this sheet 1', at the same position as in (2) above,
Laser light was irradiated in a circle of 0.0 m in the same manner as in (2) above.

(5) After repeating the steps (3) and (4) above 200 times, development was performed using methyl ethyl ketone, and a cylindrical object with a diameter of 49.0 m and a height of 11n+ was obtained.

(6) Here, the diameter of the circle irradiated with laser light (diameter 1
) is 50.0 mm, and the diameter of the obtained cylindrical object (diameter 2
) was 49.9 m, so the shrinkage rate [l-(diameter 2/
Diameter 1))X100 is 0. 2%, and there was almost no contraction.

[Effects of the Invention] According to the present invention, since a photocurable resin sheet is used as an optical three-dimensional shape forming method, handling is easy and reaction shrinkage does not occur during curing. It has the advantage that the accuracy of the three-dimensional object is extremely excellent, and the manufacturing equipment is also simple.

[Brief explanation of the drawing]

FIG. 1 is a process diagram of the present invention. 1.1′; Photocurable resin sheet 11.11'; hardened part 3; light source Patent applicant: Japan Synthetic Rubber Co., Ltd. Agent: Patent Attorney Takashi Shirai No. □ Figure 1 (stomach) (b) (B) (d)

Claims (1)

[Claims] (1) (a) Selectively irradiate a photocurable resin sheet that hardens by light irradiation with light having the energy necessary for curing, (b) Then add new photocurable resin onto the sheet after light irradiation. a step of stacking the sheets, selectively irradiating the sheets with light having the energy necessary for curing, and (c) further repeating the step (b) a predetermined number of times;
and (d) a method for forming a three-dimensional shape, which includes a step of then removing an uncured portion of the photocurable resin.