HK1057260B

HK1057260B - Solid imaging compositions for preparing polypropylene-like articles

Info

Publication number: HK1057260B
Application number: HK04100153.9A
Authority: HK
Inventors: Alan Lawton John; Prakash Chawla Chander
Original assignee: Dsm Ip财产有限公司
Priority date: 2000-03-31
Filing date: 2001-03-29
Publication date: 2008-01-25

Description

Solid imaging compositions for making polypropylene-like articles

Technical Field

The present invention discloses compositions suitable for producing objects of superior quality by solid imaging means, said objects having material properties resembling the look and feel of polypropylene articles.

Background

In the field of liquid-based solid imaging (also known as stereolithography), compositions have been developed that are capable of producing solid objects with epoxy-based and/or acrylate-based properties. Solid imaging produced objects comprised of the epoxy and/or acrylate compositions described above provide a prototype representation of the physical shape of plastic articles made upon production from materials such as ABS, nylon, polyethylene, propylene, and the like. However, such compositions lack material properties that give the user of the prototype the look and feel of the object when produced in a production material. This lack of visual and sensory accuracy in product prototyping is not merely an aesthetic issue. The look and feel of the prototype also has important engineering, design, packaging, labeling and advertising significance.

Other examples relating to the importance of appearance may arise when the article is made of certain materials. For example, the use of a clear prototype composition or a composition that is extremely opaque may mislead one to make incorrect assumptions about proper product packaging, labeling, coloring, and advertising when viewing the article.

Other considerations when trying to prototype using solid imaging include photospeed, moisture resistance, low tendency to hydrolysis, similar coefficient of friction, dimensional accuracy, ability to span without support at the time of fabrication, and wide processing tolerances.

Japanese patent application No. Hei 275618 describes epoxy and acrylate compositions for optical molded articles. The composition comprises at least 40 wt% of a cycloaliphatic epoxy resin having at least two epoxy groups per molecule.

Brief description of the invention

The photosensitive composition of the invention is characterized by having, upon exposure to actinic radiation, the following polypropylene characteristics, in particular:

(i) in the range of 1000 to 2000N/mm²Tensile modulus of (a);

(ii) an average elongation at break of at least 10%; and

(iii)24 to 40N/mm²Yield stress of (2).

Preferably, the photosensitive composition has the following polypropylene characteristics, in particular:

(i) in the range of 1000 to 2000N/mm²Tensile modulus of (a);

(ii) An average elongation at break of at least 10%;

(iii)24 to 40N/mm²Yield stress of (d); and

(iv) a tensile elongation at yield of at least 7% or no yield at all is observed.

The invention also relates to a three-dimensional article formed from a photosensitive composition comprising:

(a)30-70 wt% of a material comprising epoxy groups;

(b)5 to 35% by weight of an acrylic (hereinafter also referred to as "acrylic");

(c)0-40 wt% of a hydroxyl-containing material;

(d) at least one cationic photoinitiator; and

(e) at least one free radical photoinitiator.

The weight percentages of each component are calculated relative to the total composition whereby the amount and type of functional groups are considered as described in the specification.

In a preferred embodiment, the photosensitive composition contains 35 to 69.9% by weight of a material containing an epoxy group. Preferably, the epoxy group-containing material may have a poly (tetrahydrofuran) backbone. The composition may comprise 10-20 wt% acrylic material. Preferably, the acrylic material comprises an aromatic acrylic material, a cycloaliphatic acrylic material, or a combination thereof. The composition may comprise 10-39 wt% of the material comprising hydroxyl groups. Preferably, the material containing a hydroxyl group may be an aliphatic polycarbonate diol.

Description of the preferred embodiments

Liquid-based solid imaging is a process in which an optically formable liquid is applied as a thin layer on a surface and then imagewise exposed to actinic radiation such that the liquid is cured imagewise. Subsequently, a new thin layer of the photo-formable liquid is applied to the liquid layer or previously cured portion. The new layer is then imagewise exposed to cure the portions imagewise and cause adhesion between portions of the new hardened region and portions of the previously hardened region. Each imagewise exposure has a shape related to the relevant cross-section of the optically hardened object such that one overall optically hardened object can be removed from the surrounding liquid composition when all of the layers have been applied and all of the exposures have been completed.

One of the most important advantages of the solid-state imaging process is the ability to quickly produce actual objects that have been designed by computer aided design. A number of improvements have been made to the compositions and processes to improve the accuracy of the objects produced. Also, composition developers have made significant progress in improving individual properties such as modulus or deflection temperature of the optically hardened object. However, attempts to mimic specific physical property combinations of commonly manufactured materials, such that the manufactured materials are susceptible to being mistaken for a mimicked material based on look and feel properties, have not been successful.

During the development of the compositions disclosed herein, it was noted that by finely varying the component content, substantial changes in the look and feel of articles made by liquid-solid imaging processes could be obtained. It has surprisingly been found that by producing these changes in the composition, articles can be made which have the look and feel of articles made from polypropylene materials. In the field of liquid-solid imaging, this finding was the first time because the industrial compositions described above could not produce articles giving a look and feel similar to any other general plasticity. It is thus recognized that by varying the composition, the performance of polypropylene articles can be mimicked. This possibility thus solves the generally desired but not satisfied prototype of producing a material having not only the appearance of the desired object but also a material property that mimics the look and feel of the material from which the object produced is intended to be manufactured.

In order to mimic the look and feel of a material, appropriate appearance factors and physical properties must be determined. For example, in the field of liquid-solid imaging, the physical properties most commonly cited for fully cured parts are tensile stress, tensile modulus, elongation at break, average elongation at yield, flexural stress, flexural modulus, impact strength, hardness, and deformation temperature. Certain physical properties of these, such as elongation at break, are not "perceptible" unless the material is damaged. Such physical properties therefore have less indicative effect on the performance of a good simulated material.

In some cases, the material characteristics used to define the look and feel properties of a particular material are difficult to define. This is particularly the case where the material looks. However, in the present case, a careful combination of choices is made so that articles made by solid-state imaging means have similar coloration and light scattering characteristics to various grades of polypropylene when given varying amounts of actinic radiation. It has also been found that altering the photochemical exposure can also modify the sensory properties of articles made from the composition by solid imaging methods.

Tensile properties are the best representative of how well the article feels. "elongation at yield" is the percent elongation at yield point. For the purposes of the present invention, the yield point in a tensile stress-strain test is the point at which large increments of strain occur at constant stress. Some samples may break before or at the yield point. All tensile properties discussed herein are determined according to ASTM test D638M at temperatures in the range of 20 and 22 ℃ and humidity in the range of 20 and 30% RH.

The most important property related to the feel of the touch material is the tensile modulus so far. This is representative of the stiffness perception.

A second important property is the elongation of the material. When a model of a material is manipulated and bent, the material being modeled should not break or permanently deform if it does not break or deform for such manipulation. For plastics, there is considerable discussion regarding the point at which a sample transitions from an elastic mode of action to a plastic mode under stress. However, the most consistent opinion is that when a material begins to yield, its behavior is plastic, and any manipulation of the sample past its yield point will leave the sample permanently deformed. For the purposes of the present invention, tensile elongation at yield is used to help define this aspect of the material.

A third important physical property is tensile stress. For the purposes of the present invention, the tensile stress at which a material breaks at or before it yields is an important property for modeling purposes. A mimic material having a yield stress or fracture stress (before yielding) lower than the lowest yield stress or fracture stress of the mimic material is a less preferred mimic material.

Another important physical property is the perception of intrinsic toughness. Izod impact strength provides a good measure of the toughness of the material. A good imitation material will have a range close to the toughness of the imitation material. For the purposes of the discussion herein, impact strength is determined by notched Izod testing according to ASTM test D256A.

Generally, useful articles are not actually used at the point of fracture. For example, if a squeeze bottle is composed of a material that breaks during normal use, it will have little value. And often useful articles are not often used under stresses that cause them to pass through their yield capabilities. For example, if a bridge is designed to withstand normal loads, such as a car, which induces stresses in the support member that exceed the yield point, the bridge will increase sag from each car passing through it. Exceptions may exist for certain applications, such as living hinges. In these cases, the article is often used for the first time to induce a stress that exceeds the yield of the material, but then the stress remains within the elastic range of the material most of the time. For the purposes of the present invention, the value of the material property in terms of material fracture, for a material having a yield point, is of little value in terms of mimicking the look and feel of the material being mimicked.

The tensile stress generally quoted is the maximum tensile stress, which is either the yield stress or the fracture stress. If the material breaks before it yields, the tensile stress at break of the mimicking material should be comparable to the tensile yield stress of the mimicked material. If the mimicking material has a yield point, the tensile yield stress of the mimicking material should be comparable to the tensile yield stress of the mimicked material. In the case of polypropylene, the tensile stress at yield is from 31 to 37.3N/mm². The polypropylene mimic composition preferably has a yield stress of 24 to 40N/mm²More preferably 31 to 38N/mm²。

The tensile modulus (and/or the flexural modulus), may be the most important physical property for the feel of the material. One can usually feel the stiffness of the material and say whether the material is not sufficiently rigid or if the material is too rigid. This is because modulus is a material property determined at the working range of the material (i.e. prior to plastic deformation of the material) and is a material property that can be sensed or measured at relatively low stress levels. In general, it is suitable forThe resultant simulated material has a tensile modulus within the modulus range of the simulated material. The polypropylene has a tensile modulus in the range of about 1135 to 1550N/mm². It has been found that the resulting parts have a thickness of 1000 to 2000N/mm²The simulated composition in the tensile modulus range is a suitable simulated material for polypropylene. Components with moduli below this range are generally too soft and too deformable and therefore do not have any utility to mimic polypropylene. Conversely, components with modulus above this range are too stiff. Preferably, the composition provides the part with a tensile modulus in the range of 1100 to 1575N/mm²。

With the most preferred mimic material of polypropylene, it has been found that changes in exposure during the solid imaging process can result in significant changes in the tensile modulus. This is extremely advantageous for mimicking materials as the modulus can vary in a range very close to the modulus range of the material being mimicked. For example, such a mimetic material is thus suitable for mimicking polypropylene of various molecular weights and grades.

It is also important to mimic the elongation properties of the material. It is considered unsuitable if the simulated material has a tensile elongation at break lower than the lowest tensile elongation at yield of the simulated material. The simulated material should have a tensile elongation at yield comparable to that of the simulated material if the material has a yield point and a tensile elongation at break comparable to that of the simulated material if the material does not have a yield point. The polypropylene has a tensile elongation at yield in the range of 7-13%. Thus, a suitable mimic material for polypropylene will have a tensile elongation at break (before yielding) of 7% or greater. Preferably, the tensile elongation at yield is at least 7% or no yield at all is observed. Thus for polypropylene, the most preferred suitable mimic material will not crack or yield before 7% tensile elongation.

The impact resistance of the mimicking material is also somewhat important relative to the impact resistance of the mimicked material. For example, it is not uncommon for someone to strike a table corner with an object. From such discussion, the feel of material toughness and sound quality (barrier, tone, etc.) can be noted. For the purposes of this patent, the mock material will have an Izod impact strength that is close to that of the mock material. The polypropylene has a notched Izod impact strength of 21.4 to 74.9J/m (ASTM D256A). Thus, a suitable mimic material for polypropylene preferably has a notched Izod impact strength of at least 21J/m.

The appearance of the imitation material is also an important factor. The polypropylene had a hazy appearance. Therefore, a suitable imitation material for polypropylene should also have a hazy appearance and, as far as possible, a lowest coloration for UV-curable materials.

The compositions of the present invention generally include an epoxy group-containing material, a free radical polymerizable acrylic material, a hydroxyl group-containing material, a cationic photoinitiator, and a free radical photoinitiator.

According to the invention, the epoxy group-containing material used in the composition is a compound having on average at least one 1, 2-epoxy group in the molecule. "epoxy group" means a three-membered ring:

materials containing epoxy groups, also referred to as epoxy materials, are cationically curable, which means that polymerization and/or crosslinking and other reactions of the epoxy groups are cationically initiated. The material may be a monomer, oligomer or polymer and is sometimes referred to as a "resin". Such materials may have aliphatic, aromatic, cycloaliphatic, araliphatic or heterocyclic configurations; they include epoxy groups as pendant groups, or those groups that form part of an alicyclic or heterocyclic ring system. Those types of epoxy resins are generally known and commercially available.

The epoxy group containing material (a) should comprise at least one liquid component such that the material mixture is liquid. Thus, the epoxy group-containing material may be a single liquid epoxy material, a mixture of liquid epoxy materials or a mixture of a liquid epoxy material and a solid epoxy material soluble in the liquid.

Examples of suitable epoxy materials include polycarboxylic esters of polyglycidyl and poly (methylglycidyl), or poly (ethylene oxide) ethers of polyethers. The polycarboxylic acids may be aliphatic, such as glutaric acid, adipic acid, and the like; cycloaliphatic, such as tetrahydrophthalic acid; or aromatic, such as phthalic acid, isophthalic acid, trimellitic acid or pyromellitic acid. The polyether may be poly (tetrahydrofuran). It is likewise possible to use carboxyl-terminated adducts, for example of trimellitic acid and polyols such as glycerol or 2, 2-bis (4-hydroxycyclohexyl) propane.

Suitable epoxy materials also include polyglycidyl or poly (methylglycidyl) ethers obtainable by reacting a compound having at least one free alcoholic and/or phenolic hydroxyl group with a suitably substituted epichlorohydrin. The alcohol may be a non-cyclic alcohol such as ethylene glycol, diethylene glycol, and higher poly (ethylene oxide) glycols; cycloaliphatic, such as 1, 3-or 1, 4-dihydroxycyclohexane, bis (4-hydroxycyclohexyl) methane, 2-bis (4-hydroxycyclohexyl) propane or 1, 1-bis (hydroxymethyl) cyclohex-3-ene; or containing aromatic nuclei, such as N, N-bis (2-hydroxyethyl) aniline or p, p' -bis (2-hydroxyethylamino) diphenylmethane.

The epoxy compounds may also be derived from mononuclear phenols, for example from resorcinol or hydroquinone, or they may be based on polynuclear phenols, for example bis (4-hydroxyphenyl) methane (bisphenol F), 2-bis (4-hydroxyphenyl) propane (bisphenol a), or on phenols obtained under acidic conditions or condensation products of cresols with formaldehyde, for example phenol novolacs and cresol novolacs.

Suitable epoxy materials also include poly (N-glycidyl) compounds, which are obtained, for example, by dehydrochlorination of the reaction product of epichlorohydrin with an amine comprising at least two amine hydrogen atoms, such as N-butylamine, aniline, toluidine, m-xylylenediamine, bis (4-aminophenyl) methane or bis (4-methylaminophenyl) methane. However, the poly (N-glycidyl) compounds also include N, N '-diglycidyl derivatives of cycloalkyleneureas, such as ethyleneurea or 1, 3-propyleneurea, and N, N' -diglycidyl derivatives of hydantoins, such as 5, 5-dimethylhydantoin.

Examples of suitable epoxy materials include poly (S-glycidyl) compounds, which are di-S-glycidyl derivatives derived from dithiols such as ethane-1, 2-dithiol or bis (4-mercaptomethylphenyl) ether.

Preferably, the epoxy group-containing material is selected from bis (2, 3-epoxycyclopentyl) ether, 2, 3-epoxycyclopentyl glycidyl ether, 1, 2-bis (2, 3-epoxycyclopentyloxy) ethane, bis (4-hydroxycyclohexyl) methane diglycidyl ether, 2-bis (4-hydroxycyclohexyl) propane diglycidyl ether, 3, 4-epoxycyclohexylmethyl-3, 4-epoxycyclohexane, 3, 4-epoxy-6-methylcyclohexylmethyl-3, 4-epoxy-6-methylcyclohexanecarboxylate, bis (3, 4-epoxycyclohexylmethyl) adipate, bis (3, 4-epoxy-6-methylcyclohexylmethyl) adipate, ethylenebis (3, 4-epoxycyclohexanecarboxylate), ethanediol bis (3, 4-epoxycyclohexylmethyl) ether, vinylcyclohexene dioxide, dicyclopentadiene diepoxide, □ - (oxiranylmethyl) - □ - (oxiranylmethoxy) poly (oxy-1, 4-butanediyl), the diglycidyl ether of neopentyl glycol, or 2- (3, 4-epoxycyclohexyl-5, 5-spiro-3, 4-epoxy) cyclohexane-1, 3-dioxane, and mixtures thereof.

However, it is also possible to use epoxy resins in which the 1, 2-epoxy groups are bonded to different heteroatoms or functional groups. Those compounds include, for example, N, O-triglycidyl derivatives of 4-aminophenol, glycidyl ethers of salicylic acid, glycidyl esters, N-glycidyl-N' - (2-glycidyloxypropyl) -5, 5-dimethylhydantoin, or 2-glycidyloxy-1, 3-bis (5, 5-dimethyl-1-glycidylhydantoin-3-yl) propane.

Furthermore, liquid pre-reacted adducts of such epoxy resins with hardeners are suitable for epoxy resins.

Of course, mixtures of epoxy materials may also be used in the compositions of the present invention.

Preferred epoxy materials are cycloaliphatic diepoxides. Particularly preferred are bis (4-hydroxycyclohexyl) methane diglycidyl ether, 2-bis (4-hydroxycyclohexyl) propane diglycidyl ether, 3, 4-epoxycyclohexylmethyl-3, 4-epoxycyclohexanecarboxylate, 3, 4-epoxy-6-methylcyclohexylmethyl-3, 4-epoxy-6-methylcyclohexanecarboxylate, bis (3, 4-epoxycyclohexylmethyl) adipate, bis (3, 4-epoxy-6-methylcyclohexylmethyl) adipate, ethylenebis (3, 4-epoxycyclohexanecarboxylate), ethylene glycol bis (3, 4-epoxycyclohexylmethyl) ether, 2- (3, 4-epoxycyclohexyl-5, 5-spiro-3, 4-epoxy) cyclohexane-1, 3-dioxane, and mixtures thereof.

The epoxy material may have a wide range of molecular weights. Generally, the epoxy equivalent weight, i.e., number average molecular weight divided by the number of reactive epoxy groups, is preferably in the range of 60 to 1000.

Preferably, the composition of the present invention comprises 30 to 70 wt% of said epoxy group containing material.

According to the invention, the free radical polymerizable acrylic material used in the composition is a compound having on average at least one acrylic group, which may be a free acid or an ester. "acrylic" means the radical-CH ═ CR¹CO₂R²Wherein R is¹May be hydrogen or methyl, and R²And may be hydrogen or alkyl. "(meth) acrylate" means acrylate, methacrylate, or a mixture thereof. The acrylic material undergoes polymerization and/or crosslinking reactions initiated by free radicals. The acrylic material may be a monomerAn oligomer or a polymer. Preferably the acrylic material is a monomer or oligomer.

Suitable as acrylic component are, for example, diacrylates of cycloaliphatic or aromatic diols, such as 1, 4-dihydroxymethylcyclohexane, 2-bis (4-hydroxycyclohexyl) propane, 1, 4-cyclohexanedimethanol, bis (4-hydroxycyclohexyl) methane, hydroquinone, 4-dihydroxybiphenyl, bisphenol A, bisphenol F, bisphenol S, ethoxylated or propoxylated bisphenol A, ethoxylated or propoxylated bisphenol F, or ethoxylated or propoxylated bisphenol S, and mixtures thereof. Such acrylates are known and some of them are commercially available. Preferred compositions comprise as the acrylic component A a compound of formula I, II, III or IV

Wherein:

y is a direct bond, C1-C6 alkylene, S, O, SO₂Or CO, R10 is C1-C8 alkyl, phenyl which is unsubstituted or substituted by one or more C1-C4 alkyl groups, hydroxyl groups or halogen atoms, or of the formula CH₂A group of R11 wherein R11 is C1-C8 alkyl or phenyl, and A is a group of the formula

Or

Or compounds of any one of formulae Va to Vd as acrylic components

And the corresponding isomers thereof, and to the corresponding isomers,

or (Vd).

If the substituent is C1-C4 alkyl or C1-C8 alkyl, it may be straight-chain or branched. C1-C4 alkyl can be, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl, and C1-C8 alkyl can additionally be, for example, the various pentyl, hexyl, heptyl or octyl isomers.

If the substituent is halogen, it is fluorine, chlorine, bromine or iodine, but especially chlorine or bromine.

If the substituent is a C1-C6 alkylene group, this is, for example, methylene, ethylene, propylene (methylethylene), 1, 3-propylene, 1-propanediyl, 2-propanediyl, 1, 4-butylene, ethylmethylene, 1-butanediyl, 2-butanediyl, 1, 5-pentylene or 1, 6-hexylene. The alkylene group may also be substituted by a halogen atom. An example of a haloalkylene group is C (CCl)₃)₂And C (CF)₃)₂。

Particularly preferred in the composition are compounds of formula I, II or III, wherein Y is-CH₂-or-C (CH)₃)₂-. Also particularly preferred are compounds of formulae II and III, wherein R10 is n-butyl, phenyl, n-butoxymethyl or phenoxymethyl.

Suitable as aromatic tri (meth) acrylates are, for example, the triglycidyl ethers of triphenols and also the reaction products of phenol or cresol novolaks having three hydroxyl groups with (meth) acrylic acid. Preferably, the acrylic material is selected from the group consisting of 1, 4-dimethylol-cyclohexane diacrylate, bisphenol a diacrylate, ethoxylated bisphenol a diacrylate and mixtures thereof.

Compositions in which the acrylic component is an acrylate ester of bisphenol a diepoxide such as Ebecryl3700 ® from ucbcchemical Corporation, Smyrna, Georgia or an acrylate ester of 1, 4-cyclohexanedimethanol are particularly preferred for use in the compositions of the present invention.

Other acrylic materials may be present in addition to or in place of the aromatic or cycloaliphatic acrylic material. Liquid poly (meth) acrylates having a functionality of greater than 2 may be used in the compositions of the present invention, if appropriate. These may be, for example, tri-, tetra-or pentafunctional monomeric or oligomeric aliphatic (meth) acrylates.

Suitable as aliphatic polyfunctional (meth) acrylates are, for example, hexane-2, 4, 6-triol, the triacrylates and trimethacrylates of glycerol or 1,1, 1-trimethylolpropane, ethoxylated or propoxylated glycerol or 1,1, 1-trimethylolpropane, and hydroxyl-containing tri (meth) acrylates obtained by reacting a triepoxy compound, for example the triglycidyl ether of the triol, with a (meth) acrylate. It is likewise possible to use, for example, pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol monohydroxy tri (meth) acrylate or dipentaerythritol monohydroxy penta (meth) acrylate and mixtures thereof.

Hexafunctional urethane (meth) acrylates can likewise be used. Those urethane (meth) acrylates are known to the person skilled in the art and can be prepared by known methods, for example by reacting hydroxyl-terminated polyurethanes with acrylic or methacrylic acid or by reacting isocyanate-terminated prepolymers with hydroxyalkyl (meth) acrylates to give the urethane (meth) acrylates. Also useful are acrylates and methacrylates such as tris (2-hydroxyethyl) isocyanurate triacrylate.

The hydroxyl-containing material used in the present invention can be any liquid organic material having a hydroxyl functionality of at least 1 and preferably at least 2. The material may be a liquid or a solid that is soluble or dispersible in the remaining components. The material should be substantially free of any groups that do not substantially slow the curing reaction or are thermally or actinically unstable.

Preferably, the organic material comprises two or more primary or secondary aliphatic hydroxyl groups, which means that the hydroxyl groups are directly bonded to a non-aromatic carbon atom. The hydroxyl groups may be intramolecular or terminal. Monomers, oligomers or polymers may be used. The hydroxyl equivalent weight, i.e., number average molecular weight divided by the number of hydroxyl groups, is preferably in the range of 31 to 5000.

Representative examples of suitable organic materials having a hydroxyl functionality of 1 include alkanols, monoalkylethers of polyalkylene oxide glycols, monoalkylethers of alkylene glycols, and the like, and mixtures thereof.

Representative examples of useful monomeric polyhydroxyorganic materials include alkylene and arylalkylene diols and polyols, such as 1, 2, 4-butanetriol, 1, 2, 6-hexanetriol, 1, 2, 3-hexanetriol, 2, 6-dimethyl-1, 2, 6-hexanetriol, (2R, 3R) - (-) -2-benzyloxy-1, 3, 4-butanetriol, 1, 2, 3-hexanetriol, 1, 2, 3-butanetriol, 3-methyl-1, 3, 5-pentanetriol, 1, 2, 3-cyclohexanetriol, 1, 3, 5-cyclohexanetriol, 3,7, 11, 15-tetramethyl-1, 2, 3-cyclohexanetriol, 2-hydroxymethyltetrahydropyran-3, 4, 5-triol, 2, 4, 4-tetramethyl-1, 3-cyclobutanediol, 1, 3-cyclopentanediol, trans-1, 2-cyclooctanediol, 1, 16-hexadecanediol, 3, 6-dithio-1, 8-octanediol, 2-butyne-1, 4-diol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, 1, 7-heptanediol, 1, 8-octanediol, 1, 9-nonanediol, 1-phenyl-1, 2-ethanediol, 1, 2-cyclohexanediol, 1, 5-decalediol, 2, 5-dimethyl-3-hexyne-2, 5-diol, 2, 7-dimethyl-3, 5-octadiyne-2, 7-diol, 2, 3-butanediol, 1, 4-cyclohexanedimethanol, and mixtures thereof.

Representative examples of useful oligomeric and polymeric hydroxyl-containing materials include polyoxyethylene and polyoxypropylene diols and triols having molecular weights of from about 200 to about 10,000; polybutylene glycols of different molecular weights; a copolymer containing pendant hydroxyl groups formed from hydrolysis or partial hydrolysis of a vinyl acetate copolymer, a polyvinyl acetal resin containing pendant hydroxyl groups; hydroxyl terminated polyesters and hydroxyl terminated polylactones; hydroxy-functionalized polydienes, such as polybutadiene; aliphatic polycarbonate polyols such as aliphatic polycarbonate diols; and hydroxyl terminated polyethers, and mixtures thereof.

Preferred monomers containing hydroxyl groups are 1, 4-cyclohexanedimethanol and aliphatic and cycloaliphatic monohydric alkanols.

Preferred hydroxyl-containing oligomers and polymers include hydroxyl and hydroxyl/epoxy functionalized polybutadiene, 1, 4-cyclohexanedimethanol, polycaprolactone diols and triols, ethylene/butylene polyols, and monohydroxy functional monomers. Preferred examples of polyether polyols are polypropylene glycols and glycerol propoxylate-B-ethoxylate triols of various molecular weights. Especially preferred are linear and branched polytetrahydrofuran polyether polyols of various molecular weights, for example 250, 650, 1000, 2000 and 2900 MW.

Any type of photoinitiator that forms a cation upon exposure to actinic radiation that initiates the reaction of the epoxy material may be used in the compositions of the present invention. There are a number of known and technically proven cationic photoinitiators that are suitable for epoxy resins. They include, for example, onium salts with anions of weak nucleophilicity. Examples are halonium salts, iodosyl salts or sulfonium salts, as described for example in published European patent applications EP153904 and WO98/28663, sulfoxonium salts, as described for example in published European patent applications EP35969, 44274, 54509 and 164314, or diazonium salts, as described for example in U.S. Pat. Nos. 3,708,296 and 5,002,856. Other cationic photoinitiators are metallocene salts, as described, for example, in published European applications EP94914 and 94915.

Other popular reviews of onium salt initiators and/or metallocene salts are found in "UV Curing, Science and Technology" (edited S.P. Pappas, Technology Marketing Corp., 642 Westower Road, Stamford, conn., USA) or "Chemistry & Technology of UV & EB Formulation for coatings, Inks & Paints", volume 3 (coded by P.K. T.Oldring).

Preferred cationic photoinitiators are compounds (VI) of the formulae VI, VII or VIII

[R₁-I-R₂]⁺[Qm]^-

Wherein:

R₁、R₂、R₃、R₄、R₅、R₆and R₇Each independently is a C6-C18 aryl group which is unsubstituted or substituted with suitable groups,

l is boron, phosphorus, arsenic or antimony,

q is a halogen atom or in the anion LQ_m ^-Some of the groups Q may also be hydroxyl, and

m is an integer corresponding to the valence of L plus 1.

Examples of C6-C18 aryl are phenyl, naphthyl, anthryl and phenanthryl. Suitable any substituents are alkyl, preferably C1-C6 alkyl, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, or the various pentyl or hexyl isomers, alkoxy, preferably C1-C6 alkoxy, such as methoxy, ethoxy, propoxy, butoxy, pentyloxy or hexyloxy, alkylthio, preferably C1-C6 alkylthio, such as methylthio, ethylthio, propylthio, butylthio, pentylthio or hexylthio, halogen, such as fluorine, chlorine, bromine or iodine, amino groups, cyano groups, nitro or arylthio, such as phenylthio.

Examples of preferred halogen atoms Q are chlorine and especially fluorine. Preferred anions LQ_m ^-Is BF₄ ^-、PF₆ ^-、AsF₆ ^-、SbF₆ ^-And SbF₅(OH)^-。

Especially preferred are compositions comprising as the cationic photoinitiator a compound of formula III, wherein R₅、R₆And R₇Is an aryl group, in particular phenyl or biphenyl, or a mixture of these two compounds.

Preference is likewise given to compositions comprising as component B) a compound of the formula (IX)

[R₈(Fe¹¹R₉)_c]_d ^+c[X]_c ^-13，

Wherein the content of the first and second substances,

c is a number of 1 or 2,

d is 1, 2, 3, 4 or 5,

x is a non-nucleophilic anion, especially PF₆ ^-、AsF₆ ^-、SbF₆ ^-、CF₃SO₃ ^-、C₂F₅SO₃ ^-、n-C₃F₇SO₃ ^-、n-C₄F₉SO₃ ^-、n-C₆F₁₃SO₃ ^-Or n-C₈F₁₇SO₃ ^-R8 is a pi-arene and R9 is the anion of a pi-arene, in particular a cyclopentadienyl anion.

Examples of pi-arenes as R8 and pi-arene anions as R9 are disclosed in published European patent application EP 94915.

Examples of preferred pi-aromatics as R8 are toluene, xylene, ethylbenzene, cumene, methoxybenzene, methylnaphthalene, pyrene, perylenes, stilbenes, dibenzofurans and diphenylene sulfides. Particularly preferred are cumene, methylnaphthalene or stilbene.

Non-nucleophilic anions X^-Is FSO₃ ^-Anions of organic sulfonic acids, carboxylic acids, or anions LQ_m ^-As already defined above.

Preferred anions are derived from partially fluorinated or perfluorinated aliphatic or partially fluorinated or perfluorinated aromatic carboxylic acids, or in particular from partially fluorinated or perfluorinated aliphatic or partially fluorinated or perfluorinated aromatic organic sulfonic acids, or they are preferably anions LQ_m ^-。

Anion X^-Is BF as an example₄ ^-，PF₆ ^-，AsF₆ ^-，SbF₆ ^-，SbF₅(OH)^-，CF₃SO₃ ^-，C₂F₅SO₃ ^-，n-C₃F₇SO₃ ^-，n-C₄F₉SO₃ ^-，n-C₆F₁₃SO₃ ^-，n-C₈F₁₇SO₃ ^-，C₆F₅SO₃ ^-Phosphotungstate, or silicotungstate. Preferred is PF₆ ^-，AsF₆ ^-，SbF₆ ^-，CF₃SO₃ ^-，C₂F₅SO₃ ^-，n-C₃F₇SO₃ ^-，n-C₄F₉SO₃ ^-，n-C₆F₁₃SO₃ ^-And n-C₈F₁₇SO₃ ^-。

The metallocene salts can also be used in admixture with an oxidizing agent. Such mixtures are described in published European patent application EP 126712.

In order to increase the light efficiency or to sensitize the cationic photoinitiators to specific wavelengths, for example to a specific laser wavelength or to a specific series of laser wavelengths, sensitizers may also be used, depending on the type of initiator. Examples are polycyclic aromatic hydrocarbons or aromatic ketone compounds. Specific examples of preferred sensitizers are mentioned in published european patent application EP 153904. Other preferred sensitizers are benzopyrene, 1, 8-diphenyl-1, 3, 5, 7-octatetraene, and 1, 6-diphenyl-1, 3, 5-hexatriene, as described in U.S. Pat. No. 5,667,937. It will be appreciated that additional factors in the choice of sensitizer are the nature of the source and primary wavelength of the actinic radiation.

Any type of photoinitiator that forms free radicals when subjected to appropriate irradiation may be used in the compositions of the present invention. Typical compounds of the known photoinitiators are benzoins, such as benzoin, benzoin ethers, such as benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether, benzoin phenyl ether and acetobenzoin, acetophenones, such as acetophenone, 2-dimethoxyacetophenone, 4- (phenylthio) acetophenone and 1, 1-dichloroacetophenone, benzil ketal, such as benzil dimethyl ketal and benzil diethyl ketal, anthraquinones, such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone and 2-pentylanthraquinone, and triphenylphosphine, benzoylphosphine oxides, such as 2, 4, 6-trimethylbenzoyldiphenylphosphine oxide (Lucirin TPO), benzophenones, such as benzophenone and 4, 4 '-bis (N, N' -dimethylamino) benzophenone, thioxanthones and xanthones, acridine derivatives, phenazene derivatives, quinoxaline derivatives or 1-phenyl-1, 2-propanedione-2-O-benzoyl oxime, 1-aminophenyl ketones or 1-hydroxyphenyl ketones, such as 1-hydroxycyclohexyl phenyl ketone, phenyl (1-hydroxyisopropyl) ketone and 4-isopropylphenyl (1-hydroxyisopropyl) ketone, or triazine compounds such as 4 * -methylthiophenyl-1-bis (trichloromethyl) -3, 5-S-triazine, S-triazine-2- (stilbene) -4, 6-bistrichloromethyl, and p-methoxystyryl triazine, all of which are known.

Particularly suitable free radical photoinitiators, which are generally used in combination with lasers as radiation sources, He/Cd lasers, operating at, for example, 325nm, an argon ion laser, operating at, for example, 351nm, or 351 and 364nm, or 333, 351 and 364nm, or a triple frequency YAG solid-state laser, having an output of 351 or 355nm, are acetophenones, such as 2, 2-dialkoxybenzophenones and 1-hydroxyphenyl ketones, for example 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-1- {4- (2-hydroxyethoxy) phenyl } -2-methyl-1-propanone or 2-hydroxyisopropylphenyl ketone (also known as 2-hydroxy-2, 2-dimethylacetophenone), but especially 1-hydroxycyclohexyl phenyl ketone. Another class of free radical photoinitiators comprises benzil ketals, such as benzil dimethylketal. In particular, alpha-hydroxyphenyl ketone, benzildimethyl ketal or 2, 4, 6-trimethylbenzoyldiphenylphosphine oxide is used as photoinitiator.

Another suitable class of free radical photoinitiators includes ionic dye-counter ion compounds, which are capable of actinic radiation and generating free radicals, which can initiate polymerization of acrylates. The compositions of the present invention comprising ionic dye-counterion compounds are thus capable of curing in a more tunable manner using visible light in a tunable wavelength range of 400 to 700 nanometers. Ionic dye-counter ion compounds and their mode of action are known, for example from published european patent application EP223587 and U.S. Pat. nos. 4,751,102, 4,772,530 and 4,772,541. Suitable ionic dye-counter ion compounds which may be mentioned by way of example may be anionic dye-iodonium ion complexes, anionic dye-pyrylium ion complexes and especially cationic dye-borate anion compounds, which have the following general formula

Wherein D is⁺Is a cationic dye and R₁₂、R₁₃、R₁₄And R₁₅Each independently is an alkyl, arylalkylaryl, allyl, aralkyl, alkenyl, alkynyl, alicyclic, or saturated or unsaturated heterocyclic group. For the group R₁₂To R₁₅A preferred definition of (a) can be found, for example, in published european patent application EP 223587.

Especially preferred is the free radical photoinitiator 1-hydroxyphenyl ketone, which after final curing gives parts having the lowest color of yellow and provides articles most closely mimicking polypropylene.

Other additives known to be useful in solid imaging compositions may also be present in the compositions of the present invention. Stabilizers are often added to the composition to prevent viscosity build-up during use in the solid imaging process. Preferred stabilizers are described in U.S. Pat. No. 5,665,792. Such stabilizers are typically hydrocarbon carboxylates of group IA and IIA metals. Most preferred examples of such salts are sodium bicarbonate, potassium bicarbonate and rubidium carbonate. Rubidium carbonate is preferred for the formulations of the present invention, preferably in an amount of 0.0015 to 0.005% by weight of the composition. The selective stabilizers are polyvinylpyrrolidone and polyacrylonitrile. Other possible additives include dyes, pigments, fillers, antioxidants, wetting agents, photosensitizers for free radical photoinitiators, leveling agents, surfactants, and the like.

The liquid radiation-curable composition may also comprise any conventional cationically polymerizable organic compound, either alone or in a mixture with at least one other compound which can be cationically polymerized or polymerized by other mechanisms, for example by means of free radicals.

These include, for example, ethylenically unsaturated compounds which can be polymerized by a cationic mechanism, such as monoolefins and diolefins, for example isobutene, butadiene, isoprene, styrene, a-methylstyrene, divinylbenzene, N-vinylpyrrolidone, N-vinylcarbazole and acrolein, or vinyl ethers, for example vinyl methyl ether, isobutyl vinyl ether, trimethylolpropane trivinyl ether, ethylene glycol divinyl ether; cyclic vinyl ethers, such as 3, 4-dihydro-2-formyl-2H-pyran (dimeric acrolein), and 3, 4-dihydro-2H-pyran-2-carboxylate and vinyl esters of 2-hydroxymethyl-3, 4-dihydro-2H-pyran, such as vinyl acetate and vinyl stearate. They may also be cationically polymerizable heterocyclic compounds, such as ethylene oxide, propylene oxide, epichlorohydrin, glycidyl ethers or monohydric alcohols or phenols, such as n-butyl glycidyl ether, n-octyl glycidyl ether, phenyl glycidyl ether and cresyl glycidyl ether; glycidyl acrylate, glycidyl methacrylate, styrene oxide, and cyclohexene oxide; oxetanes such as 3, 3-dimethyloxetane and 3, 3-bis (chloromethyl) oxetane; tetrahydrofuran; dioxolane, trioxane and 1, 3, 6-trioxane; lactones such as beta-propiolactone, gamma-valerolactone and epsilon-caprolactone; spiro ether (spiroether) carbonate spiroether ester; thiiranes, such as ethylene sulfide and propylene sulfide; an epoxy resin; linear and branched polymers containing glycidyl groups in the side chains, such as homo-and copolymers of polyacrylate and polymethacrylate glycidyl esters. Other suitable cationically polymerizable compounds are methylol compounds which include amino resins, such as N-methylol-, N-methoxymethyl-, N-N-butoxymethyl and N-acetoxymethyl derivatives of amides or amide-like compounds, for example cyclic ureas, such as ethyleneurea (imidazolin-2-one), hydantoin, urone (tetrahydroxyoxadiazin-4-one), 1, 2-propyleneurea (4-methylimidazolin-2-one), 1, 3-propyleneurea (hexahydro-2H-pyrimidin-2-one), hydroxypropyleneurea (5-hydroxyhexahydro-2H-pyrimidin-2-one), 1, 3, 5-melamine and other polytriazines, such as acetoguanamine, benzomelamine, and adipoguanamine (adipoguanamine). If desired, it is also possible to use amino resins which contain both N-methylol and N-acetoxymethyl groups, for example hexamethylolmelamine, in which 1 to 3 of the hydroxyl groups have been etherified with methyl groups. Other suitable methylol compounds are phenolic resins, especially resole resins prepared from phenols and aldehydes. Phenols suitable for this purpose include phenol, resorcinol, 2-bis (p-hydroxyphenyl) propane, p-chlorophenol, phenols substituted by one or two alkyl groups each having from 1 to 9 carbon atoms, for example o-, m-or p-cresol, xylenol, p-tert-butylphenol and p-nonylphenol, and phenyl-substituted phenols, especially p-phenylphenol. The aldehyde condensed with the phenols is preferably formaldehyde, but other aldehydes such as acetaldehyde and furfural are also suitable. Mixtures of such curable phenolic resins may be used if desired.

It is sometimes advantageous to describe in equivalents or milliequivalents per 100 grams of material comprising epoxy groups in the total composition. The epoxy equivalent weight may be derived by dividing the molecular weight of a molecule by the number of epoxy groups contained within the molecule. The total epoxy equivalent weight of the composition is determined by first calculating the epoxy content of the individual components, i.e. epoxy group containing materials, epoxy-acrylates, and the like. The single component epoxy equivalent weights are weighted averaged to yield the epoxy equivalent weight of the entire composition.

The composition of the present invention preferably comprises 10% to 20% by weight of a free radical polymerizable acrylic material, based on the total weight of the composition. Most preferably the acrylic is an aromatic and/or cycloaliphatic diacrylate or dimethacrylate.

The composition of the present invention preferably comprises 10% to 20% by weight of hydroxyl-containing material, based on the total weight of the composition.

It is sometimes advantageous to describe the equivalents or milliequivalents of material comprising hydroxyl groups per 100 grams of the total composition. The hydroxyl equivalent weight can be derived by dividing the molecular weight of a molecule by the number of hydroxyl groups contained within the molecule. The total number of equivalents of hydroxyl groups in the composition is determined by first calculating the hydroxyl content of each component, i.e., epoxy group-containing material, epoxy-acrylate, polyol, initiator, and the like. The weighted average of the hydroxyl equivalent weights of the individual components yields the hydroxyl equivalent weight of the entire composition. All hydroxyl groups are assumed to be reactive, independent of steric hindrance. Preferably, the ratio of epoxy equivalents to hydroxyl equivalents is in the range of 1.5 to 3.8, more preferably 1.8 to 3.4.

In describing the epoxy polymerizable component, the acrylic polymerizable component, the hydroxyl group-containing component, the cationic initiator, and the components of the radical initiator classes in the formulation, the following criteria are used. Components containing only epoxy functional groups, hydroxyl functional groups, or ethylenic unsaturation (acrylic functional groups) are calculated in their respective polymerizable classes on a total weight basis. Those components which contain ethylenic unsaturation or both a free radical initiator and hydroxyl groups, such as acrylate 1 (see examples) and 1-hydroxycyclohexyl phenyl ketone, fall into the 50: 50 weight to corresponding categories. Those components containing epoxy, hydroxyl and ethylenic unsaturation, such as epoxy 5 (see examples), are classified into the corresponding categories on an 1/3 weight basis. Antioxidants are calculated in the antioxidant class on a total weight basis. Cationic initiators are calculated on a total weight basis in the cationic initiator class. When used in the calculation of the class of components during manufacture, the components may have an imperfect reactive conversion (e.g., by conversion with epichlorohydrin from the polyol to the polyglycidyl) which the calculation does not take into account. However, when calculating the ratio of epoxy equivalent to hydroxyl equivalent, the supplier measured and mentioned epoxy value is used for the calculation.

The compositions of the present invention preferably comprise from about 0.2 to about 10 weight percent of a cationic photoinitiator, based on the total weight of the composition.

The compositions of the present invention preferably comprise from about 0.01 to about 10 weight percent of a free radical photoinitiator, based on the total weight of the composition.

The compositions of the present invention may be prepared according to conventional procedures. Typically, the components are mixed by mixing in any suitable mixing device. In some cases, certain components may be pre-mixed prior to addition to the total composition. In some cases, the mixing is performed in the absence of light. In some cases, the mixing is carried out with appropriate heating, typically at a temperature of about 30 ℃ to about 60 ℃.

The process for producing three-dimensional articles from the compositions of the present invention generally involves exposing successive thin layers of the liquid composition to actinic radiation. The thin layer of the photosensitive composition of the present invention is applied to a surface. This may most conveniently be done if the composition is a liquid. However, the solid composition may be melted to form a layer. The thin layer is then imagewise exposed to actinic radiation to form a first imaged cross-section. The radiation must provide sufficient exposure to cause substantial curing of the photosensitive composition in the exposed areas. "substantially cured" refers to the photosensitive composition having reacted to such an extent that the exposed regions are physically distinguishable from the unexposed regions. For liquid, gel, or semi-solid photosensitive compositions, the cured regions will be hardened or cured to a non-liquid form. For a solid photosensitive composition, the exposed regions will have a higher melting point than the unexposed regions. Preferably, the exposure is such that a portion of each adjacent layer is bonded to a portion of the previously exposed layer or carrier region or to a portion of the platform surface. An additional (second) thin layer of the photosensitive composition is then applied to the first imaged cross-section and imagewise exposed to actinic radiation to form an additional (second) imaged cross-section. These steps are repeated, with a thin "nth layer" of the photosensitive composition being applied to the "n-1 th layer" of the imaged cross-section and exposed to actinic radiation. The repetition is performed a sufficient number of times to constitute the entire three-dimensional article.

The preferred range of the radiation is 280-650 nm. Any convenient actinic radiation may be usedA source, but a laser is particularly suitable. Useful lasers include HeCd, argon, nitrogen, metal vapor and NdYAG lasers. The preferred range of the exposure energy is 10-150mJ/cm². Suitable methods and apparatus for performing the exposure and producing three-dimensional articles have been described, for example, in U.S. patents 4,987,044, 5,014,207 and 5,474,719, which teach the use of pseudoplastomers, plastic fluids, thixotropic fluids, gels, semi-solid and solid photopolymer materials in the solid imaging process.

Typically, the three-dimensional article formed by exposure to actinic radiation, as discussed above, is not fully cured, meaning that not all of the reactive species in the composition have reacted. Thus, there is often an additional step of more completely curing the article. This can be achieved by further irradiation with actinic radiation, heating, or both. Exposure to actinic radiation may be effected using any convenient source of radiation, typically an ultraviolet lamp, for exposure times of from about 10 to over 60 minutes. The heating is typically carried out at a temperature of about 75-150 c for about 10 to over 60 minutes.

Examples

The components 3, 4-epoxycyclohexylmethyl-3, 4-epoxycyclohexanecarboxylate (epoxy 1), 1, 2-epoxytetradecane (epoxy 2), diglycidyl ether of neopentyl glycol (epoxy 4), trimethylolpropane triacrylate (acrylate 2), polytetrahydrofuran straight chain (1000mw) (polyol 2), polytetrahydrofuran straight chain (650mw) (polyol 3), polytetrahydrofuran straight chain (250mw) (polyol 4), 1, 4-Cyclohexanedimethanol (CHDM) (polyol 5), 1-hydroxycyclohexylphenylketone (free radical initiator; FRI) are commercially available from Aldrich Chemical Company Inc. (Milwaukee, Wis.). α - (oxiranylmethyl) - ω - (oxiranylmethoxy) poly (oxy-1, 4-butanediyl) (MW780) (epoxy 3) is available from EMS Chemie (Sumpter, SC). Partially acrylated bisphenol a epoxy (epoxy 5) and diacrylate epoxy of bisphenol a (acrylate 1) are available from UCB Chemicals Corp. 1, 4-cyclohexanedimethanol diacrylate (acrylate 3) is sold by Sartomer Company (Exton, Pa.). Aliphatic polycarbonate diol (MW860) (polyol 1) is available from Stahl USA (Pea body, MA). Triaryl sulfonium hexafluoroantimonate (cationic photoinitiator, Catl) mixed in 50 wt% propylene carbonate is sold by Union carbide Chemicals and Plastics company Inc. (Danbury, CT). Thiodiethylene bis- (3, 5-di-tert-butyl-4-hydroxy) hydrocinnamate (antioxidant) is sold by Ciba (Hawthorne, NY).

The individual components were weighed, mixed, then heated to 50 ℃ and mixed for several hours until all ingredients were completely dissolved.

For all formulations, the exposure-to-working curve of the formulation was determined using methods well known in the art. The working curve is a measure of the speed at which a particular material is exposed. Which represents the relationship between the thickness of the floating layer, scanned over the photopolymer surface in a vat or petri dish, produced as a function of a given exposure. Parts were made by forming a series of 6 mil (0.15mm) coating layers and imagewise imparting sufficient exposure to each layer to produce a cure equivalent to a 10 mil (0.254mm) working curve thickness.

All parts were fabricated using an argon ion laser operating at either 351nm or 355nm output.

After the parts are formed, they are washed in a solvent, dried and then completely cured. All parts were UV post-cured for 60 minutes in a post-cure apparatus manufactured by 3D Systems, inc. (Valencia, CA).

All tensile properties were measured according to ASTM test D638M. Temperature and humidity of example components were controlled during testing: the temperature is about 20-22 deg.C and the humidity is about 20-30% RH. The properties of the compositions detailed herein tend to change over time as further crosslinking occurs. All physical property tests were performed approximately one week after post-curing of the test parts. The samples were stored for 7 days under the test conditions: temperature about 20-22 ℃ and humidity 20-30% RH. Table 6 contains yield point elongation (%) values: all the different values of the test samples from the specific examples lie within the ranges mentioned in the table. If "unyielding" is mentioned, no yielding is observed during the test and the test specimen breaks during the test experiment, the values are represented in the column for average elongation at break.

The impact strength of all samples was determined by notched Izod testing according to ASTM test D256A.

For polypropylene, The physical test values are obtained from a variety of sources, including Modem plastics Encyclopedia' 98, published in 11 months 1997, The McGraw-Hill Companies, Inc., New York, New York.

Examples 1 to 23

The compositions of the present invention were prepared having the components listed in tables 1-5. Amounts are listed in weight percent.

TABLE 1

Composition (I)	Example 1	Example 2	Example 3	Example 4	Example 5
Composition (I)	Example 1	Example 2	Example 3	Example 4	Example 5	Epoxy 1	33.8	47.6	43.7	43.1	46.4
Epoxy 3		22.0			21.5	Epoxy 1	33.8	47.6	43.7	43.1	46.4
Epoxy 3		22.0			21.5	Epoxy 4	15.0
Acrylic ester 1	25.0	24.0	10.0	12.0	26.0	Epoxy 4	15.0
Acrylic ester 1	25.0	24.0	10.0	12.0	26.0	Acrylic ester 2			11.0	13.0
Polyol 1	18.0		25.0	24 0		Acrylic ester 2			11.0	13.0
Polyol 1	18.0		25.0	24 0		Polyol 5			2.0
Catl	4.6	2.5	4.3	4.1	2.7	Polyol 5			2.0
Catl	4.6	2.5	4.3	4.1	2.7	FRI	3.4	3.7	3.8	3.6	3.2
Antioxidant agent	0.2	0.2	0.2	0.2	0.2	FRI	3.4	3.7	3.8	3.6	3.2
Antioxidant agent	0.2	0.2	0.2	0.2	0.2	% epoxy	48.8	69.6	43.7	43.1	67.9
% acrylic acid ester	12.5	12.0	16.0	19.0	13.0	% epoxy	48.8	69.6	43.7	43.1	67.9
% acrylic acid ester	12.5	12.0	16.0	19.0	13.0	% of hydroxyl groups	32.2	13.9	33.9	31.8	14.6
％Catl	4.6	2.5	4.3	4.1	2.7	% of hydroxyl groups	32.2	13.9	33.9	31.8	14.6
％Catl	4.6	2.5	4.3	4.1	2.7	％FRI	1.7	1.9	1.9	1 8	1.6
Epoxy/hydroxyl equivalent weight	2.41	3.57	2.36	2.8	3.33	％FRI	1.7	1.9	1.9	1 8	1.6

TABLE 2

Composition (I)	Example 6	Example 7	Example 8	Example 9	Example 10
Composition (I)	Example 6	Example 7	Example 8	Example 9	Example 10	Epoxy 1	43.8	45.5	38.5	46.4	44.4
Epoxy 3				21.5		Epoxy 1	43.8	45.5	38.5	46.4	44.4
Epoxy 3				21.5		Epoxy 4			15.0
Acrylic ester 1	10.0	24.0	8.0	26.0	11.0	Epoxy 4			15.0
Acrylic ester 1	10.0	24.0	8.0	26.0	11.0	Acrylic ester 2	11.0		9.0		12 0
Acrylic ester 3		3.5				Acrylic ester 2	11.0		9.0		12 0
Acrylic ester 3		3.5				Polyol 1	25.0		15.0		24.5
Polyol 2		21.0				Polyol 1	25.0		15.0		24.5
Polyol 2		21.0				Polyol 5	2.0		6.0
Catl	4.8	2.6	4.1	2.7	4.5	Polyol 5	2.0		6.0
Catl	4.8	2.6	4.1	2.7	4.5	FRI	3.2	3.3	4.2	3.2	3.4
Antioxidant agent	0.2	0.1	0.2	0.2	0.2	FRI	3.2	3.3	4.2	3.2	3.4
Antioxidant agent	0.2	0.1	0.2	0.2	0.2	% epoxy	43.8	45.5	53.5	67.9	44.4
% acrylic acid ester	16.0	15.5	13.0	13.0	17.5	% epoxy	43.8	45.5	53.5	67.9	44.4
% acrylic acid ester	16.0	15.5	13.0	13.0	17.5	% of hydroxyl groups	33.6	34.7	27.1	14.6	31.7
％Catl	4.8	2.6	4.1	2.7	4.5	% of hydroxyl groups	33.6	34.7	27.1	14.6	31.7
％Catl	4.8	2.6	4.1	2.7	4.5	％FRI	1.6	1.7	2.1	1.6	1.7
Epoxy/hydroxyl equivalent weight	2.42	2.25	2.39	3.33	2.98	％FRI	1.6	1.7	2.1	1.6	1.7

TABLE 3

Composition (I)	Example l1	Example 12	Example 13	Example 14	Example 15
Composition (I)	Example l1	Example 12	Example 13	Example 14	Example 15	Epoxy 1	46.4	39.3	46.8	41.7	45.4
Epoxy 3	21.5				22.5	Epoxy 1	46.4	39.3	46.8	41.7	45.4
Epoxy 3	21.5				22.5	Epoxy 5				6.0
Acrylic ester 1	26.0	24.0	12.0	7.0	26.0	Epoxy 5				6.0
Acrylic ester 1	26.0	24.0	12.0	7.0	26.0	Acrylic ester 2			13.0	11.0
Acrylic ester 3		3.5				Acrylic ester 2			13.0	11.0
Acrylic ester 3		3.5				Polyol 1		25.0		24.0
Polyol 3			15.0			Polyol 1		25.0		24.0
Polyol 3			15.0			Polyol 4			4.0
Polyol 5				2.0		Polyol 4			4.0
Polyol 5				2.0		Catl	2.7	4.8	5.4	4.3	2.7
FRI	3.2	3.2	3.6	3.8	3.2	Catl	2.7	4.8	5.4	4.3	2.7
FRI	3.2	3.2	3.6	3.8	3.2	Antioxidant agent	0.2	0.2	0.2	0.2	0.2
% epoxy	67.9	39.3	46.8	43.7	67.9	Antioxidant agent	0.2	0.2	0.2	0.2	0.2
% epoxy	67.9	39.3	46.8	43.7	67.9	% acrylic acid ester	13.0	15.5	19.0	16.5	13.0
% of hydroxyl groups	14.6	38.6	26.8	33.4	14.6	% acrylic acid ester	13.0	15.5	19.0	16.5	13.0
% of hydroxyl groups	14.6	38.6	26.8	33.4	14.6	％Catl	2.7	4.8	5.4	4.3	2.7
％FRI	1.6	1.6	1.8	1.9	1.6	％Catl	2.7	4.8	5.4	4.3	2.7
％FRI	1.6	1.6	1.8	1.9	1.6	Epoxy/hydroxyl equivalent weight	3.33	1.82	2.45	2.35	3.28

TABLE 4

Composition (I)	Example 16	Example 17	Example 18	Example 19	Example 20
Composition (I)	Example 16	Example 17	Example 18	Example 19	Example 20	Epoxy 1	37.5	45.4	44.3	41.9	47.7
Epoxy 3		22.5		21.0		Epoxy 1	37.5	45.4	44.3	41.9	47.7
Epoxy 3		22.5		21.0		Epoxy 5	25.0
Acrylic ester 1		26.0	24.0	24.0	12.0	Epoxy 5	25.0
Acrylic ester 1		26.0	24.0	24.0	12.0	Acrylic ester 2	9.0				13.0
Acrylic ester 3			3.50	3.6		Acrylic ester 2	9.0				13.0
Acrylic ester 3			3.50	3.6		Polyol 1	19.0		20.0
Polyol 3					16.0	Polyol 1	19.0		20.0
Polyol 3					16.0	Polyol 4					2.0
Polyol 5	1.0			3.5		Polyol 4					2.0
Polyol 5	1.0			3.5		Catl	4.1	2.7	4.6	2.6	5.5
FRI	4.2	3.2	3.4	3.3	3.6	Catl	4.1	2.7	4.6	2.6	5.5
FRI	4.2	3.2	3.4	3.3	3.6	Antioxidant agent	0.2	0.2	0.2	0.2	0.2
% epoxy	45.8	67.9	44.3	62.9	47.7	Antioxidant agent	0.2	0.2	0.2	0.2	0.2
% epoxy	45.8	67.9	44.3	62.9	47.7	% acrylic acid ester	17.3	13.0	15.5	15.6	19.0
% of hydroxyl groups	30.4	14.6	33.7	17.1	25.8	% acrylic acid ester	17.3	13.0	15.5	15.6	19.0
% of hydroxyl groups	30.4	14.6	33.7	17.1	25.8	％Catl	4.1	2.7	4.6	2.6	5.5
％FRI	2.1	1.6	1.7	1.6	1.8	％Catl	4.1	2.7	4.6	2.6	5.5
％FRI	2.1	1.6	1.7	1.6	1.8	Epoxy/hydroxyl equivalent weight	3.13	3.28	2.18	2.31	2.75

TABLE 5

Composition (I)	Example 21	Example 22	Example 23
Composition (I)	Example 21	Example 22	Example 23	Epoxy 1	35.7	45.8	43.3
Epoxy 2		5.0		Epoxy 1	35.7	45.8	43.3
Epoxy 2		5.0		Epoxy 3			22.5
Epoxy 5	27.0			Epoxy 3			22.5
Epoxy 5	27.0			Acrylic ester 1		25.0	26
Acrylic ester 2	10.0			Acrylic ester 1		25.0	26
Acrylic ester 2	10.0			Polyol 1	18.0	16.0
Polyol 5	1.0			Polyol 1	18.0	16.0
Polyol 5	1.0			Catl	4.3	4.6	4.8
FRI	3.8	3.4	3.2	Catl	4.3	4.6	4.8
FRI	3.8	3.4	3.2	Antioxidant agent	0.2	0.2	0.2
% epoxy	44.7	50.8	65.8	Antioxidant agent	0.2	0.2	0.2
% epoxy	44.7	50.8	65.8	% acrylic acid ester	19.0	12.5	13.0
% of hydroxyl groups	29.9	30.2	14.6	% acrylic acid ester	19.0	12.5	13.0
% of hydroxyl groups	29.9	30.2	14.6	％Catl	4.3	4.6	4.8
％FRI	1.9	1.7	1.6	％Catl	4.3	4.6	4.8
％FRI	1.9	1.7	1.6	Epoxy/hydroxyl equivalent weight	2.49	2.48	3.15

The compositions of the present invention were exposed and tested as described above. Examples 2,5, 7,9, 11, 15, 17 and 19 were exposed at 351 nm. Examples 1, 3, 4, 6, 8, 10, 12, 13, 14, 16, 18 and 20-23 were exposed at 355 nm. The properties are shown in Table 6 below.

TABLE 6

	Tensile modulus (N/mm)²)	Elongation at yield Point (%)	Average elongation at Break (%)	Yield stress (N/mm)²)
	Tensile modulus (N/mm)²)	Elongation at yield Point (%)	Average elongation at Break (%)	Yield stress (N/mm)²)	Polypropylene	1135 to 1550	7.0 to 13.0	100 to 200	31 to 37.3
Example 1	1119	7.7 to unyielding	21	26	Polypropylene	1135 to 1550	7.0 to 13.0	100 to 200	31 to 37.3
Example 1	1119	7.7 to unyielding	21	26	Example 2	1135	Not yielding	12.4	26.2
Example 3	1194	5.1 to 5.9	23.2	27.2	Example 2	1135	Not yielding	12.4	26.2
Example 3	1194	5.1 to 5.9	23.2	27.2	Example 4	1202	5.0 to 7.2	16.1	28.9
Example 5	1299	4.6 to unyielding	11.5	30.7	Example 4	1202	5.0 to 7.2	16.1	28.9
Example 5	1299	4.6 to unyielding	11.5	30.7	Example 6	1322	4.0 to 5.3	30.3	32.9
Example 7	1331	Not yielding	20.3	32.9	Example 6	1322	4.0 to 5.3	30.3	32.9
Example 7	1331	Not yielding	20.3	32.9	Example 8	1378	4.1 to 4.4	29.4
Example 9	1403	7 to unyielding	10.8	32.8	Example 8	1378	4.1 to 4.4	29.4
Example 9	1403	7 to unyielding	10.8	32.8	Example 10	1404	4.8 to 5.0	21.2	33.64
Example 11	1418	4.2 to unyielding	13.8	32.9	Example 10	1404	4.8 to 5.0	21.2	33.64
Example 11	1418	4.2 to unyielding	13.8	32.9	Example 12	1432	6.7 to 6.1	29.4	31.8
Example 13	1443	4.8 to 5.0	22.6	32.2	Example 12	1432	6.7 to 6.1	29.4	31.8
Example 13	1443	4.8 to 5.0	22.6	32.2	Example 14	1487	4.6 to 4.7	31	32.7
Example 15	1555	3.9 to 5.2	12.2	35.9	Example 14	1487	4.6 to 4.7	31	32.7
Example 15	1555	3.9 to 5.2	12.2	35.9	Example 16	1558	4.3 to 4.5	19.3	32
Example 17	1565	3.9 to 5.2	12.2	35.9	Example 16	1558	4.3 to 4.5	19.3	32
Example 17	1565	3.9 to 5.2	12.2	35.9	Example 18	1666	4.8 to 5.1	15.3	34.2
Example 19	1667	4.7 to 5.0	15.5	35.8	Example 18	1666	4.8 to 5.1	15.3	34.2
Example 19	1667	4.7 to 5.0	15.5	35.8	Example 20	1787	4.4 to 4.5	23.9	40.2
Example 21	1840	4.2 to 4.5	11.9	35.9	Example 20	1787	4.4 to 4.5	23.9	40.2
Example 21	1840	4.2 to 4.5	11.9	35.9	Example 22	1947	5 to 5.5	11.3	34.2
Example 23	1405	6.7 to unyielding	16.5	33.6	Example 22	1947	5 to 5.5	11.3	34.2

The formulations in examples 1-23 produced parts having a hazy appearance that looked like polypropylene. The tensile modulus and elongation at yield are advantageous for mimicking the feel of polypropylene. The notched Izod impact strength (ASTM D256) of example 9 was 33.36J/m. The flexural modulus and flexural strength of example 9, as determined by the 3-point flexural test (ASTM790), were 1300MPa and 63MPa, respectively. These values are advantageously matched to the flexural modulus of polypropylene.

Claims

1. A photosensitive composition, comprising:

(a)30-70 wt% of a material comprising epoxy groups;

(b) 5-35% by weight of an acrylic;

(c) at least one cationic photoinitiator; and

(d) at least one free radical photoinitiator;

characterized in that the composition further comprises a component selected from epoxy group containing materials having a poly (tetrahydrofuran) backbone, or polytetrahydrofuran polyether polyols, or aliphatic polycarbonate polyols, and the composition has the following characteristics after full curing:

(i) in the range of 1000 to 2000N/mm²Tensile modulus of (a);

(ii) an average elongation at break of at least 10%; and

(iii)24 to 40N/mm²Yield stress of (2).

2. The composition of claim 1, wherein the composition, after being fully cured, has the following characteristics:

(i) in the range of 1100 to 1575N/mm²Tensile modulus of (a);

(ii) an average elongation at break of at least 10%; and

(iii)31 to 38N/mm²Yield stress of (2).

3. The composition of claim 1 or 2, wherein the aliphatic polycarbonate polyol is an aliphatic polycarbonate diol and the acrylic is a liquid poly (meth) acrylate having a functionality greater than 2.

4. The composition of claim 1 or 2, wherein the composition comprises a polytetrahydrofuran polyether polyol and the acrylic is a liquid multi (meth) acrylate having a functionality greater than 2.

5. The photosensitive composition of claim 1 or 2, wherein the material containing an epoxy group is a cycloaliphatic diepoxide.

6. The photosensitive composition according to claim 1 or 2, wherein the epoxy group-containing material comprises a compound selected from the group consisting of: bis (2, 3-epoxycyclopentyl) ether, 2, 3-epoxycyclopentyl glycidyl ether, 1, 2-bis (2, 3-epoxycyclopentyloxy) ethane, bis (4-hydroxycyclohexyl) methane diglycidyl ether, 2-bis (4-hydroxycyclohexyl) propane diglycidyl ether, diglycidyl ether of neopentyl glycol, 3, 4-epoxycyclohexylmethyl-3, 4-epoxycyclohexanecarboxylate, 3, 4-epoxy-6-methylcyclohexylmethyl-3, 4-epoxy-6-methylcyclohexanecarboxylate, bis (3, 4-epoxycyclohexylmethyl) adipate, bis (3, 4-epoxy-6-methylcyclohexylmethyl) adipate, ethylenebis (3, 4-epoxycyclohexanecarboxylate), ethanediol bis (3, 4-epoxycyclohexylmethyl) ether, vinylcyclohexene dioxide, dicyclopentadiene diepoxide, 1, 2-epoxytetradecane, bis (oxiranyl) poly (oxy-1, 4-butanediyl), partially acrylated bisphenol a epoxy, and 2- (3, 4-epoxycyclohexyl-5, 5-spiro-3, 4-epoxy) cyclohexane-1, 3-dioxane, and mixtures thereof.

7. A photosensitive composition according to claim 1 or 2, wherein said acrylic is selected from aromatic acrylics, cycloaliphatic acrylics or mixtures thereof.

8. The photosensitive composition of claim 7, wherein the acrylic is bisphenol A acrylate diepoxide or 1, 4-cyclohexanedimethanol acrylate.

9. The photosensitive composition of claim 1 or 2, wherein the acrylic is a liquid multi (meth) acrylate having a functionality greater than 2.

10. The photosensitive composition of claim 4, wherein the liquid poly (meth) acrylate is selected from the group consisting of: hexane-2, 4, 6-triol, triacrylates and trimethacrylates of glycerol or 1,1, 1-trimethylolpropane, ethoxylated or propoxylated glycerol or 1,1, 1-trimethylolpropane, and hydroxyl-containing tri (meth) acrylates obtained from the reaction of triepoxy compounds.

11. The photosensitive composition of claim 4, wherein the liquid poly (meth) acrylate is selected from pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol monohydroxy tri (meth) acrylate or dipentaerythritol monohydroxy penta (meth) acrylate, and mixtures thereof.

12. The photosensitive composition of claim 1 or 2, wherein the acrylic is selected from the group consisting of 1, 4-dimethylolcyclohexane diacrylate, bisphenol a diacrylate, trimethylolpropane triacrylate, and ethoxylated bisphenol a diacrylate, and mixtures thereof.

13. The photosensitive composition of claim 1 or 2, wherein the composition comprises 10 to 39% by weight of polytetrahydrofuran polyether polyol.

14. The photosensitive composition of claim 1 or 2, wherein the polytetrahydrofuran polyether polyol has a molecular weight between 250 and 2900 MW.

15. Use of the photosensitive composition of claim 1 in the manufacture of an article by solid imaging means, wherein the article has the following properties:

(i) in the range of 1000 to 2000N/mm²Tensile modulus of (a);

(ii) an average elongation at break of at least 10%; and

(iii)24 to 40N/mm²Yield stress of (2).

16. A three-dimensional article formed from the photosensitive composition of claim 1 by solid imaging means, wherein the article has:

(i) in the range of 1000 to 2000N/mm²Tensile modulus of (a);

(ii) an average elongation at break of at least 10%; or

(iii)24 to 40N/mm²Yield stress of (2).

17. The three-dimensional article of claim 16, wherein the article has:

(i) in the range of 1000 to 1600N/mm²Tensile modulus of (a);

(ii) an average elongation at break of at least 10%;

(iii)28 to 40N/mm²Yield stress of (d); and

18. A method of forming a three-dimensional article comprising:

(1) applying a layer of a composition to a surface, wherein the composition is as defined in any one of claims 1 to 14;

(2) imagewise exposing the layer to actinic radiation to form an imaged cross-section, wherein the radiation is of sufficient intensity to cause substantial curing of the layer in the exposed areas;

(3) coating a layer of the composition on the previously exposed imaged cross-section;

(4) imagewise exposing the thin layer from step (3) to actinic radiation to form an additional imaged cross-section, wherein the radiation is of sufficient intensity to cause substantial curing of the thin layer in the exposed areas and to cause adhesion to the previously exposed imaged cross-section;

(5) repeating steps (3) and (4) a sufficient number of times to form a three-dimensional article.

19. The method as recited in claim 18, wherein said actinic radiation is in the range of 280-650 nm.

20. The method of claim 18 or 19, wherein the exposure energy is in the range of 10 to 150mJ/cm²。