JP2019172924A - Support material for laminate molding - Google Patents

Abstract

To provide a support material for laminate molding excellent in biodegradability, and excellent in adhesiveness with a model material even when polypropylene is used as the model material.SOLUTION: A support material for laminate molding contains a polyvinyl alcohol resin and an acid modified polyolefin resin.SELECTED DRAWING: None

Description

  The present invention relates to a support material for additive manufacturing that is used for additive manufacturing and is finally removed.

  Laminated modeling is a method of modeling a three-dimensional object having a predetermined structure. After a fluid material is extruded, it is solidified, and an article is modeled by further laminating the material thereon. . As the layered manufacturing method, a UV curing method, a hot melt lamination method, and the like have been proposed. However, since the apparatus structure is simple, the hot melt lamination method is widely used.

  The material constituting the three-dimensional object is called a model material, and various types of resins have been studied as the model material. Acrylonitrile, butadiene, styrene (ABS) resin, polylactic acid (PLA), and the like have been used from the viewpoint of melt moldability, thermal stability, and mechanical properties after solidification, but in recent years polypropylene (PP) has been used. is increasing.

  There are various structures in a three-dimensional object to be layered, and in some cases, a part that does not exist in the process of forming a three-dimensional object may include a part that cannot be formed unless it is supported by something else. In such a case, when the three-dimensional object is manufactured, a support portion that supports a portion (that is, a void portion) that does not exist in the structure of the original three-dimensional object is provided below the three-dimensional object in the gravity direction. The material forming the support portion is referred to as a support material, and the support portion is formed as necessary during the modeling process and finally removed.

  As a method for removing the support portion, there are a method of removing mainly by dissolving in a liquid after modeling, a method of removing by scraping, a method of removing by blowing with a liquid or gas, and the like. However, in the method of removing the support part by scraping, it is difficult to scrape the three-dimensional object so as not to be damaged when the three-dimensional object has a complicated shape, and in the method of removing by blowing, the strength must be set so that it can be blown away. Therefore, there is a problem that the strength is insufficient to support the three-dimensional object. Therefore, a support material that can be removed by dissolving in a liquid after modeling has been proposed (see, for example, Patent Document 1).

  As a water-soluble resin that can be washed and removed and used as a support material, an amorphous polyvinyl alcohol resin (hereinafter, “polyvinyl alcohol” is also referred to as “PVA”) has been proposed, and the PVA resin is flexible. It has been proposed to add a styrene-ethylene-butylene-styrene block copolymer (SEBS), which is a styrenic thermoplastic elastomer, in order to impart properties (for example, see Patent Document 2).

JP 2014-24329 A International Publication No. 2015/1822681

However, when polypropylene is used as the model material and PVA resin is used as the support material, the adhesion of the support material to the model material is not sufficient, and the accuracy of the obtained three-dimensional object may be reduced. Therefore, a support material having improved adhesion to polypropylene as a model material has been demanded.
Under such a background, the present invention aims to provide a support material for layered modeling that can stably perform modeling even when polypropylene is used as a model material and has excellent adhesion to the model material. To do.

  As a result of intensive studies, the present inventor has found that the above problem can be solved by using a support material containing a polyvinyl alcohol (PVA) resin and an acid-modified polyolefin resin grafted with an acid. It came to complete.

That is, the present invention is characterized by the following (1) to (6).
(1) A layered modeling support material comprising a polyvinyl alcohol resin and an acid-modified polyolefin resin.
(2) 10-80 parts by mass of the acid-modified polyolefin resin is contained with respect to 100 parts by mass of the polyvinyl alcohol-based resin.
(3) The support material for additive manufacturing according to (1) or (2) above, further comprising an acid-modified block copolymer.
(4) The additive for layered modeling according to (3), wherein the acid-modified block copolymer is contained in an amount of 2 to 20 parts by mass with respect to 100 parts by mass of the polyvinyl alcohol resin.
(5) The layered modeling support material according to any one of (1) to (4), wherein the acid-modified polyolefin resin is an acid-modified polypropylene resin.
(6) The additive manufacturing method according to any one of (1) to (5), wherein the polyvinyl alcohol resin is a polyvinyl alcohol resin having a 1,2-diol structure in a side chain. Support material.

  According to the layered modeling support material of the present invention, since it is excellent in adhesiveness with polypropylene (PP), the shape of the three-dimensional object can be modeled as designed during modeling.

  The support material for additive manufacturing of the present invention forms a sea-island structure in which the PVA-based resin is a sea component and the polyolefin-based resin is an island component, and the island-based polyolefin-based resin is acid-modified, By finely dispersing, it is presumed that the adhesion with the model material (PP) is improved.

It is a figure which shows typically the manufacturing process of the solid thing (modeled object for adhesion | attachment evaluation) which consists of a model material and a support material. It is a figure for demonstrating the test method using the molded article for adhesion | attachment evaluation.

Hereinafter, although embodiment of this invention is described in detail, this invention is not limited to the following embodiment.
In the present specification, (meth) allyl means allyl or methallyl, (meth) acryl means acryl or methacryl, and (meth) acrylate means acrylate or methacrylate.

The laminated structure support material of this embodiment contains a polyvinyl alcohol (PVA) resin and an acid-modified polyolefin resin grafted with an acid.
Each resin will be described below.

(PVA resin)
PVA resin is a resin mainly composed of vinyl alcohol structural units, obtained by saponifying polyvinyl ester resins obtained by polymerizing vinyl ester monomers, and saponified with vinyl alcohol structural units corresponding to the degree of saponification. It is composed of vinyl ester structural units remaining without being.

  Examples of the vinyl ester monomers include vinyl formate, vinyl acetate, vinyl propionate, vinyl valelate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate. Vinyl acetate, etc., vinyl acetate is preferably used economically.

  The average degree of polymerization (measured in accordance with JIS K6726) of the PVA resin is usually 150 to 4000, preferably 200 to 2000, more preferably 250 to 800, and further preferably 300 to 600. It is. If the average degree of polymerization is too low, it tends to be difficult to form a stable shape during melt molding, and if it is too high, the viscosity of the resin composition tends to be too high and melt molding tends to be difficult. .

Moreover, the viscosity at the time of making it aqueous solution may be used as a parameter | index of the polymerization degree of PVA-type resin, The viscosity of the aqueous solution of PVA-type resin used by this embodiment is as a viscosity of 4 weight% aqueous solution in 20 degreeC, Usually, it is 1.5-20 mPa * s, Preferably it is 2-12 mPa * s, Most preferably, it is 2.5-8 mPa * s. If the viscosity is too low, it tends to be difficult to form a stable shape during melt molding, and if it is too high, the viscosity of the resin composition tends to be too high, making melt molding difficult.
In addition, in this embodiment, the viscosity of the aqueous solution of PVA-type resin is a viscosity of 4 weight% aqueous solution in 20 degreeC measured based on JISK6726.

The degree of saponification of the PVA-based resin is usually 70 to 99.9 mol%, preferably 75 to 98.5 mol%, particularly preferably 78 to 90 mol%. If the degree of saponification is too low, the flexibility becomes too high and the shape stability at the time of lamination tends to decrease.
The degree of saponification was measured according to JIS K 6726.

  The melting point of the PVA-based resin is usually 120 to 230 ° C, preferably 150 to 220 ° C, and particularly preferably 160 to 190 ° C. If the melting point is too high, the processing temperature at the time of melt molding becomes high and the resin may be deteriorated. If it is too low, the shape stability of the melt molding tends to decrease.

  In the case of ordinary PVA-based resins, the main chain bonding mode is mainly 1,3-diol bonds, and the content of 1,2-diol bonds is about 1.5 to 1.7 mol%. The content can be increased by increasing the polymerization temperature when polymerizing the vinyl ester monomer, and the content should be 1.8 mol% or more, and further 2.0 to 3.5 mol%. However, it is preferable in terms of improving the affinity with the acid-modified polyolefin resin.

  As the PVA-based resin used in the present embodiment, a modified PVA-based resin can also be used. For example, the copolymer is copolymerized with a vinyl ester-based monomer and a copolymerizable monomer, and the obtained copolymer is saponified. Examples thereof include copolymer-modified PVA resins obtained by post-modification and post-modified PVA resins obtained by post-modifying PVA resins.

  Examples of the monomer copolymerized with the vinyl ester monomer used in the copolymerization-modified PVA resin include olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, α-octadecene, and the like; Unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid or salts thereof, mono- or dialkyl esters, etc .; nitriles such as acrylonitrile and methacrylonitrile; amides such as acrylamide and methacrylamide Olefin sulfonic acids such as ethylene sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid or salts thereof; alkyl vinyl ethers, N-acrylamidomethyltrimethylammonium chloride, allyltrimethylammonium chloride, dimethyl Polyoxyalkylene (meth) allyl ethers such as allyl vinyl ketone, N-vinyl pyrrolidone, vinyl chloride, vinylidene chloride, polyoxyethylene (meth) allyl ether, polyoxypropylene (meth) allyl ether; polyoxyethylene (meth) acrylate , Polyoxyalkylene (meth) acrylates such as polyoxypropylene (meth) acrylate; polyoxyalkylene (meth) acrylamides such as polyoxyethylene (meth) acrylamide and polyoxypropylene (meth) acrylamide; polyoxyethylene (1- ( (Meth) acrylamide-1,1-dimethylpropyl) ester, polyoxyethylene vinyl ether, polyoxypropylene vinyl ether, polyoxyethylene allylamine, polyoxypropylene Hydroxy group-containing α-olefins such as allylamine, polyoxyethylene vinylamine, polyoxypropylene vinylamine, 3-buten-1-ol, 4-penten-1-ol, 5-hexen-1-ol, and acylated products thereof And the like.

  Examples of the post-modified PVA resin include those having an acetoacetyl group by reaction with diketene, those having a polyalkylene oxide group by reaction with ethylene oxide, and hydroxyalkyl groups by reaction with an epoxy compound. And those obtained by reacting an aldehyde compound having various functional groups with a PVA resin.

  The amount of modification in such a modified PVA resin, that is, the constituent unit derived from various monomers in the copolymer, or the content of the functional group introduced by post-reaction is generally different depending on the modified species. Although it cannot be said, it is usually 0.1 to 20 mol%, and a range of 0.5 to 15 mol% is particularly preferably used.

  In the present embodiment, the PVA-based resin is preferably a melt-moldable PVA-based resin from the viewpoint of widespread use. Examples of melt-moldable PVA resins include PVA resins having primary hydroxyl groups in the side chains, ethylene-modified PVA resins having structural units derived from ethylene, alkylene oxide group-modified PVA resins having a polyalkylene oxide group, etc. From the viewpoint of lowering the melting point, a PVA resin having a primary hydroxyl group in the side chain is preferable.

  Examples of the PVA resin having a primary hydroxyl group in the side chain include, for example, a PVA resin having a 1,2-diol structure in the side chain, a PVA resin having a hydroxyalkyl group in the side chain (for example, a hydroxymethyl group in the side chain) PVA-based resin having Among these, a PVA resin having a 1,2-diol structure in the side chain represented by the following general formula (1) (hereinafter sometimes referred to as “1,2-diol-containing PVA resin”) is more preferable. .

(In Formula (1), R < ¹ > -R < ⁶ > represents a hydrogen atom or a C1-C4 alkyl group each independently, and X represents a single bond or a coupling chain.)

  The portion other than the 1,2-diol structural unit of the 1,2-diol-containing PVA resin is a vinyl alcohol structural unit and a vinyl ester structural unit of an unsaponified portion, as in a normal PVA resin.

In the general formula (1), the alkyl group having 1 to 4 carbon atoms of R ^{1 to} R ⁶ is, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl. And may have a substituent such as a halogen group, a hydroxyl group, an ester group, a carboxylic acid group, or a sulfonic acid group, if necessary.
R ^{1 to} R ⁶ may all be the same or different, but all of them are hydrogen atoms, so that the terminal of the side chain becomes a primary hydroxyl group, and the reactivity with the functional group of the acid-modified polyolefin resin is improved. This is desirable.

In addition, the bond chain (X) in the general formula (1) includes hydrocarbon groups such as alkylene groups, alkenylene groups, alkynylene groups, phenylene groups, and naphthylene groups (these hydrocarbon groups are fluorine atoms, chlorine atoms, bromine atoms). another halogen atom may be substituted with) _{etc., -O -., - (CH} 2 O) m -, - (OCH 2) m -, - (CH 2 O) m CH 2 -, - _{CO -, - COCO -, -} CO (CH 2) m CO -, - CO (C 6 H 4) CO -, - S -, - CS -, - SO -, - SO 2 -, - NR -, - CONR -, - NRCO -, - CSNR -, - NRCS -, - NRNR -, - HPO 4 -, - Si (OR) 2 -, - OSi (OR) 2 -, - OSi (OR) 2 O -, - _{Ti (OR) 2 -, -} OTi (OR) 2 -, - OTi (OR _{2 O -, - Al (OR} ) -, - OAl (OR) -, - OAl (OR) O-, etc. (R is an optional substituent each independently hydrogen atom, an alkyl group preferably, also m is an integer of 1 to 5.).
X is preferably a single bond, an alkylene group having 6 or less carbon atoms (particularly a methylene group), or —CH ₂ OCH ₂ — in terms of stability during production or use, and among them, in terms of thermal stability and high temperature. A single bond is most preferable from the viewpoint of stability under acidic conditions.

The modification rate (content) of the PVA-based resin having a primary hydroxyl group in the side chain is usually 0.1 to 20 mol%, preferably 0.5 to 15 mol%, more preferably 1 to 10 mol. %, Particularly preferably 2 to 8 mol%. If the modification rate is too low, the reactivity with the functional group of the acid-modified polyolefin resin tends to decrease, and if it is too high, the crystallization rate becomes too slow and the shape tends to be deformed during lamination.
Such a modification rate is calculated from an integral value measured by ¹ H-NMR (300 MHz proton NMR, d6-DMSO solution, internal standard substance: tetramethylsilane, 50 ° C.).

  The average degree of polymerization (measured in accordance with JIS K6726) of the PVA resin having a primary hydroxyl group in the side chain is usually 150 to 4000, preferably 200 to 2000, and more preferably 250 to 800. More preferably, it is 300-500. If the average degree of polymerization is too low, it tends to be difficult to form a stable shape during melt molding, and if it is too high, the viscosity of the resin composition tends to be too high and melt molding tends to be difficult. .

The viscosity of the PVA resin having a primary hydroxyl group in the side chain is usually 1.5 to 20 mPa · s, preferably 2 to 12 mPa · s, as the viscosity of a 4 wt% aqueous solution at 20 ° C. Preferably it is 2.5-8 mPa * s. If the viscosity is too low, it tends to be difficult to form a stable shape during melt molding, and if it is too high, the viscosity of the resin composition tends to be too high, making melt molding difficult.
In this embodiment, the viscosity of the aqueous solution of the PVA resin having a primary hydroxyl group in the side chain is the viscosity of a 4 wt% aqueous solution at 20 ° C. measured in accordance with JIS K 6726.

The saponification degree of the PVA resin having a primary hydroxyl group in the side chain is usually 70 to 99.9 mol%, preferably 75 to 98.5 mol%, particularly preferably 78 to 90 mol%. . If the degree of saponification is too low, the flexibility becomes too high and the shape stability at the time of lamination tends to decrease.
The degree of saponification was measured according to JIS K 6726.

Such a PVA resin having a primary hydroxyl group in the side chain can be produced by a known production method. In particular, a description will be given taking a 1,2-diol-containing PVA resin as an example. The 1,2-diol-containing PVA resin can be produced, for example, by the methods described in JP-A Nos. 2002-284818, 2004-285143, and 2006-95825.
That is, (i) a method of saponifying a copolymer of a vinyl ester monomer and a compound represented by the following general formula (2), (ii) a vinyl ester monomer and vinyl ethylene represented by the following general formula (3) A method of saponifying and decarboxylating a copolymer with carbonate; (iii) a copolymer of a vinyl ester monomer and 2,2-dialkyl-4-vinyl-1,3-dioxolane represented by the following general formula (4): The polymer can be produced by a method of saponification and deketalization.

(In Formula (2), R < ¹ > -R < ⁶ > represents a hydrogen atom or a C1-C4 alkyl group each independently, X represents a single bond or a bond chain, R < ⁷ > and R <^8> are respectively independent. And represents a hydrogen atom or R ⁹ —CO— (wherein R ⁹ is an alkyl group having 1 to 4 carbon atoms).

(In Formula (3), R < ¹ > -R < ⁶ > represents a hydrogen atom or a C1-C4 alkyl group each independently, and X represents a single bond or a coupling chain.)

(In Formula (4), R < ¹ > -R < ⁶ > represents a hydrogen atom or a C1-C4 alkyl group each independently, X represents a single bond or a bond chain, R < ¹⁰ > and R <^11> are respectively independent. And represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)

Specific examples and preferred examples of R ^{1 to} R ⁶ and X in the formulas (2) to (4) are the same as those in the above formula (1), and R ^{7 to} R ¹¹ have 1 to 1 carbon atoms. Specific examples and preferred examples of the alkyl group 4 are the same as in the case of the formula (1).

Among the above methods, the method (i) is preferable in that it is excellent in copolymerization reactivity and industrial handling. In particular, in the compound represented by the general formula (2), R ^{1 to} R ⁶ are hydrogen atoms. , X is a single bond, R ⁷ and R ⁸ are R ⁹ —CO—, and R ⁹ is preferably an alkyl group having 1 to 4 carbon atoms, among which 3,4-diasiloxy-1-butene is preferable, and among them, R ⁹ 3,4-diacetoxy-1-butene in which is a methyl group is preferably used.

  The PVA resin used in the present embodiment may be one kind or a mixture of two or more kinds. In that case, the above-mentioned unmodified PVA resins, unmodified PVA resins, and various modified substances are used. The combination with PVA-type resin, especially PVA-type resin which has a 1, 2- diol structure, etc. can be mentioned. Moreover, the combination etc. of PVA-type resin from which saponification degree, polymerization degree, modification rate, etc. differ can also be mentioned.

(Acid-modified polyolefin resin)
The acid-modified polyolefin resin is a polyolefin resin grafted with an acid. The acid-modified polyolefin resin is obtained, for example, by copolymerizing an olefin monomer and a monomer having a carboxyl group or an acid anhydride group, or by grafting a monomer having a carboxyl group or an acid anhydride group to the polyolefin resin. It is done.

  Examples of the olefin monomer include ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, 4,4-dimethyl-1-pentene, 1-hexene, 4 Examples include α-olefins having about 2 to 20 carbon atoms such as methyl-1-hexene, 1-heptene, 1-octene, 1-decene, and 1-octadecene.

  Examples of polyolefin resins include ethylene homopolymers, propylene homopolymers, copolymers of ethylene and other monomers, copolymers of propylene and other monomers, etc. Include the above-mentioned α-olefin, vinyl acetate, vinyl alcohol, (meth) acrylic acid, (meth) acrylate, and the like.

Specific examples of polyolefin-based resins include ethylene homopolymers such as high-pressure low-density polyethylene (LDPE) and high-density polyethylene (HDPE), ethylene / propylene copolymers, ethylene / butene copolymers, and ethylene / hexene copolymers. Polymer, ethylene / octene copolymer, ethylene / propylene / butene copolymer, ethylene / propylene / hexene copolymer, ethylene / propylene / octene copolymer, ethylene / butene / hexene copolymer, ethylene / butene / octene Copolymer, ethylene-α-olefin copolymer such as ethylene / hexene / octene copolymer, and ethylene / vinyl acetate copolymer, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic Acid methyl copolymer, ethylene- (meth) ethyl acrylate copolymer Ethylene-based polymers such as ethylene- (meth) acrylic acid-methyl (meth) acrylate copolymer; propylene homopolymer (propylene homopolymer), propylene / ethylene random copolymer, propylene / butene random copolymer, Propylene / ethylene / hexene random copolymer, propylene / ethylene / octene random copolymer, propylene / butene / hexene random copolymer, propylene / butene / octene random copolymer, propylene / hexene / octene random copolymer, Examples thereof include propylene polymers such as propylene / ethylene block copolymers; butene polymers.
Here, the ethylene-based polymer, the propylene-based polymer, and the butene-based polymer refer to resins containing ethylene, propylene, or butene in a composition of 50 mol% or more of monomer units, respectively. These polyolefin resins can be used alone or in combination of two or more.

  In this embodiment, an ethylene homopolymer that is an ethylene polymer, an ethylene-α-olefin copolymer, an ethylene / vinyl acetate copolymer, a propylene homopolymer that is a propylene polymer, and propylene / ethylene random A copolymer is preferable because it is inexpensive and easily available, and is excellent in economic efficiency. Further, from the viewpoint of mechanical properties, an ethylene homopolymer, an ethylene / α-olefin copolymer, a propylene homopolymer, and a propylene / ethylene random copolymer are preferable, and a propylene homopolymer and a propylene / ethylene random copolymer are preferable. Is more preferable.

Examples of the monomer having a carboxyl group or an acid anhydride group include unsaturated dicarboxylic acids such as maleic acid, fumaric acid, chloromaleic acid, hymic acid, citraconic acid, and itaconic acid; acrylic acid, butanoic acid, crotonic acid, and vinyl. Unsaturated monocarboxylic acids such as acetic acid, methacrylic acid, pentenoic acid, dodecenoic acid, linoleic acid, angelic acid and cinnamic acid; maleic anhydride, hymic anhydride, itaconic anhydride, citraconic anhydride, anhydrides of acrylic acid, etc. Examples thereof include acid anhydrides of the above unsaturated dicarboxylic acids or unsaturated monocarboxylic acids.
The monomer which has a carboxyl group or an acid anhydride group may be used individually by 1 type, or may be used in combination of 2 or more type. Among these, maleic anhydride is particularly preferable because of its good compatibility with PVA resins and block copolymers.

  The acid-modified polyolefin resin used in this embodiment is obtained by graft-modifying the unsaturated carboxylic acid or unsaturated carboxylic acid anhydride to the polyolefin resin from the viewpoint of compatibility with the PVA resin or block copolymer. A thing can be used suitably.

  Here, “graft modification” means that an unsaturated carboxylic acid or an unsaturated carboxylic acid anhydride is not used as a copolymer component of a polyolefin resin, but is produced by reacting an unsaturated carboxylic acid by reaction with an already produced polyolefin resin. An acid or an unsaturated carboxylic acid anhydride is bonded. That is, in the present invention, “graft modification” means not only a case where an unsaturated carboxylic acid or unsaturated carboxylic acid anhydride is introduced as a side chain having a long chain length relative to the skeleton of the polyolefin resin, but also a polyolefin resin. It is included if it is chemically bonded to.

  The graft modification of the polyolefin resin can be performed by various conventionally known methods. Although the modification method is not limited, (i) a melt modification method in which an unsaturated carboxylic acid or an unsaturated carboxylic acid anhydride is added to a melted polyolefin resin and graft copolymerized, (ii) a polyolefin system dissolved in a solvent Examples thereof include a solution modification method in which an unsaturated carboxylic acid or an unsaturated carboxylic acid anhydride is added to the resin and graft copolymerized. Among these, from the viewpoint of hygiene, a melt modification method that does not require the use of a solvent is preferable, and graft modification using an extruder is more preferable. For efficient graft modification, modification in the presence of a radical initiator is preferred.

  The acid-modified polyolefin resin may be composed of only a graft-modified polyolefin resin, or may be a mixture of a polyolefin resin and the same or different unmodified polyolefin resin.

  In this embodiment, the acid-modified polyolefin resin is an acid-modified polypropylene resin obtained by graft-modifying a polypropylene resin with an unsaturated carboxylic acid or an unsaturated carboxylic acid anhydride in that it is excellent in compatibility with the PVA resin. A resin is preferable, and a maleic anhydride-modified polypropylene obtained by graft-modifying polypropylene with maleic anhydride is more preferable.

  The acid modification rate (content) of the acid-modified polyolefin resin is preferably 0.05 to 10.0% by mass, more preferably 0.1 to 5.0% by mass, and 0.2 to 2. 0% by mass is more preferable. If the acid modification rate is too low, extrusion melt molding tends to become unstable, and if too high, extrusion melt moldability tends to be difficult.

Although the density of the acid-modified polyolefin resin is not limited, usually ^{0.85g / cm 3 ~0.96g / cm 3} , preferably ^{0.87g / cm 3 ~0.95g / cm 3} . If the density is too small, suspended matter tends to be generated on the surface of the water when dissolved, and if it is too large, the precipitate tends to remain at the bottom.

  The melt flow rate (MFR) of the acid-modified polyolefin resin is not particularly limited, but is preferably 0.01 to 50 g / 10 minutes, more preferably 0.1 to 10 g / 10 minutes from the viewpoint of moldability. The MFR of the acid-modified polyolefin resin means a value at 190 ° C. and a load of 2.16 kg when the resin is based on an ethylene polymer or a butene polymer, and is a resin based on a propylene polymer. The case means a value at 230 ° C. and a load of 2.16 kg.

  In the layered modeling support material, the acid-modified polyolefin resin is preferably contained at a ratio of 10 to 80 parts by mass with respect to 100 parts by mass of the PVA resin. Adhesiveness with polypropylene can be improved by adding an acid-modified polyolefin resin to 10 parts by mass or more with respect to 100 parts by mass of PVA resin, and high water dispersion by making it 80 parts by mass or less. (Water solubility) can be maintained. The acid-modified polyolefin-based resin is more preferably 10 to 60 parts by mass, and still more preferably 20 to 40 parts by mass with respect to 100 parts by mass of the PVA-based resin.

(Acid-modified block copolymer)
It is preferable that the layered modeling support material of the present embodiment further contains an acid-modified block copolymer. The acid-modified block copolymer is obtained by reacting an unmodified block copolymer with one or more of unsaturated carboxylic acid anhydride or unsaturated dicarboxylic acid under heating, and reacts with a hydroxyl group in the side chain. It is a block copolymer having a block having a functional group that can be obtained. By having the acid-modified block copolymer in the layered modeling support material, it is possible to improve particularly the peelability and molding stability.

  The block copolymer used in the present embodiment has a polymer block of an aromatic vinyl compound typified by styrene as a hard segment, and a polymer block of a conjugated diene compound or such a polymer as a soft segment. A block in which part or all of the double bonds remaining in the block are hydrogenated, or a polymer block of isobutylene is included. In particular, such a block copolymer preferably has a functional group capable of reacting with a hydroxyl group in the side chain. Specifically, a carboxylic acid group or a derivative group thereof (hereinafter referred to as “carboxylic acid group” may be abbreviated). .) Are preferably used.

  The constitution of each block in the block copolymer is as follows. When the hard segment is represented by A and the soft segment is represented by B, the diblock copolymer represented by AB, ABA or B- A triblock copolymer represented by A-B and a polyblock copolymer in which A and B are alternately connected can be exemplified, and the structure also includes linear, branched, star-shaped, etc. Can do. Among these, a linear triblock copolymer represented by ABA in terms of mechanical properties is preferable.

  As a monomer used for forming a polymer block of an aromatic vinyl compound that is a hard segment, for example, styrene; α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, alkyl styrene such as t-butylstyrene, 2,4-dimethylstyrene, 2,4,6-trimethylstyrene; halogenated styrene such as monofluorostyrene, difluorostyrene, monochlorostyrene, dichlorostyrene, methoxystyrene; vinyl naphthalene, vinyl Examples thereof include vinyl compounds having an aromatic ring other than a benzene ring, such as anthracene, indene, and acetonaphthylene, and derivatives thereof. The polymer block of the aromatic vinyl compound may be a homopolymer block of the above-described monomer or a copolymer block of a plurality of monomers, but a styrene homopolymer block is preferably used.

  The polymer block of the aromatic vinyl compound may be a copolymer obtained by copolymerizing a small amount of monomers other than the aromatic vinyl compound as long as the effects of the present invention are not impaired. Examples of such monomers include butene, pentene, and hexene. Examples thereof include olefins such as butadiene, isoprene and other diene compounds, methyl vinyl ether and other vinyl ether compounds and allyl ether compounds, and the copolymerization ratio is usually 10 mol% or less of the entire polymer block.

  The weight average molecular weight of the polymer block of the aromatic vinyl compound in the block copolymer is usually 10,000 to 300,000, in particular 20,000 to 200,000, more preferably 50,000 to 100,000. Those are preferably used.

  Moreover, as a monomer used for formation of the polymer block which is a soft segment, for example, 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), 2,3-dimethyl-1,3-butadiene Conjugated diene compounds such as 1,3-pentadiene, and isobutylene, and these may be used alone or in combination. Of these, a homopolymer block or copolymer block of isoprene, butadiene, and isobutylene is preferable, and a homopolymer block of butadiene or isobutylene is particularly preferably used.

In the case of such a polymer block of a conjugated diene compound, a plurality of bonding forms may be taken by polymerization. For example, in butadiene, a butadiene unit (—CH ₂ —CH (CH═CH ₂ ) by 1,2-bonding is used. -) And 1,4-bonded butadiene units (—CH ₂ —CH═CH—CH ₂ —) are formed. Since these production ratios vary depending on the type of conjugated diene compound, it cannot be generally stated, but in the case of butadiene, the ratio of 1,2-bond production is usually in the range of 20 to 80 mol%.

The polymer block of such a conjugated diene compound can improve the heat resistance and weather resistance of the styrenic thermoplastic elastomer by hydrogenating part or all of the remaining double bonds. The hydrogenation rate at that time is preferably 50 mol% or more, and particularly preferably 70 mol% or more.
By this hydrogenation, for example, the butadiene unit of 1,2-bond of butadiene becomes a butylene unit (—CH ₂ —CH (CH ₂ —CH ₃ ) —), and the butadiene unit generated by the 1,4-bond is Two continuous ethylene units (—CH ₂ —CH ₂ —CH ₂ —CH ₂ —) are formed, but usually the former is preferred.

  In addition, the polymer block which is such a soft segment may be a copolymer obtained by copolymerizing a small amount of monomers other than the above-mentioned monomers within the range that does not impair the effects of the present invention. Examples of such monomers include aromatic vinyl compounds such as styrene. Olefins such as butene, pentene, and hexene, vinyl ether compounds such as methyl vinyl ether, and allyl ether compounds. The copolymerization ratio thereof is usually 10 mol% or less of the entire polymer block.

  Further, the weight average molecular weight of the polymer block derived from the conjugated diene compound or isobutylene in the block copolymer is usually 10,000 to 300,000, particularly 20,000 to 200,000, and further 50, Those having a viscosity of 000 to 100,000 are preferably used.

  As described above, in the block copolymer used in the present invention, the hard segment is a polymer block of an aromatic vinyl compound, the soft segment is a polymer block of a conjugated diene compound, or a part of the residual double bond, Alternatively, all of them are composed of a hydrogenated polymer block, an isobutylene polymer block, and the like, and typical examples thereof include, for example, a styrene / butadiene block copolymer (SBS) and SBS using styrene and butadiene as raw materials. Styrene / butadiene / butylene block copolymer (SBBS) in which side chain double bonds are hydrogenated in the butadiene structural unit, and styrene / ethylene / butylene block copolymer (SEBS) in which main chain double bonds are hydrogenated. ), Styrene / isoprene broth made from styrene and isoprene Click copolymer (SIPS), styrene / isobutylene block copolymer of styrene and isobutylene as a raw material (SIBS) and the like can be illustrated, among others thermal stability, SEBS or SIBS has excellent weather resistance is preferably used.

  The content ratio of the polymer block of the aromatic vinyl compound that is the hard segment and the polymer block that is the soft segment in the block copolymer is usually 10/90 to 70/30 in weight ratio, A range of 20/80 to 50/50 is preferred. If the content ratio of the polymer block of the aromatic vinyl compound is too much or too little, the balance between the flexibility and rubber elasticity of the block copolymer may be lost, and as a result, the support material of the present invention is peeled off. In some cases, characteristics such as property are insufficient.

A block copolymer is obtained by obtaining a block copolymer having a polymer block of an aromatic vinyl compound and a polymer block of a conjugated diene compound or isobutylene, and further, if necessary, a block copolymer in the polymer block of the conjugated diene compound. It can be obtained by hydrogenating heavy bonds.
First, as a method for producing a block copolymer having a polymer block of an aromatic vinyl compound and a conjugated diene compound or an isobutylene polymer block, a known method can be used. And a method of sequentially polymerizing an aromatic vinyl compound and a conjugated diene compound or isobutylene in an inert organic solvent.
Next, as a method of hydrogenating the block copolymer having the polymer block of the aromatic vinyl compound and the polymer block of the conjugated diene compound, a known method can be used, for example, a borohydride compound, etc. And a method using a reducing agent, hydrogen reduction using a metal catalyst such as platinum, palladium, Raney nickel, and the like.

  The acid-modified block copolymer used in this embodiment has a functional group capable of reacting with a hydroxyl group in the side chain. Such a functional group is particularly preferably a carboxylic acid, and by using a block copolymer having a functional group capable of reacting with a hydroxyl group in the side chain, a support material particularly excellent in peelability and molding stability is obtained. It becomes possible.

The content of the carboxylic acid in the block copolymer, the acid value measured by titration method, usually, a 0.5~20mgCH ₃ ONa / g, especially 1~10mgCH ₃ ONa / g, further 1.5 Those having ˜3 mg CH ₃ ONa / g are preferably used.
If the acid value is too low, the effect of introducing a functional group cannot be sufficiently obtained, and if it is too high, the melt viscosity of the support material tends to be too high due to a crosslinking reaction.
In adjusting the acid value, in addition to adjusting the introduction amount of the functional group, the content of the functional group is adjusted by mixing a block copolymer having a functional group and a block copolymer having no functional group. A method is mentioned.

  As a method for introducing such a functional group containing a carboxylic acid into the block copolymer, a known method can be used. For example, α, β- during production of the block copolymer, that is, during copolymerization, A method of copolymerizing an unsaturated carboxylic acid or a derivative thereof or a method of adding an α, β-unsaturated carboxylic acid or a derivative thereof to the block copolymer after production of the block copolymer is preferably used. Examples of such an addition method include a method using a radical reaction in a solution in the presence or absence of a radical initiator, and a method of melt kneading in an extruder.

  Examples of the α, β-unsaturated carboxylic acid or derivative thereof used for introducing the carboxylic acid group include α, β-unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid; maleic acid, succinic acid, itaconic acid, Examples include α, β-unsaturated dicarboxylic acids such as phthalic acid; α, β-unsaturated monocarboxylic acid esters such as glycidyl acrylate, glycidyl methacrylate, hydroxyethyl acrylate, and hydroxymethyl methacrylate. In addition, the carboxylic acid group introduced into the block copolymer of the present invention may form an acid anhydride structure with an adjacent carboxylic acid group, maleic anhydride, succinic anhydride, itaconic anhydride, Examples thereof include α, β-unsaturated dicarboxylic acid anhydrides such as phthalic anhydride.

The weight average molecular weight of the acidic group block copolymer used in this embodiment is usually from 50,000 to 500,000, particularly from 120,000 to 450,000, more preferably from 150,000 to 400,000. Preferably used.
If the weight average molecular weight is too large or too small, a morphology in which the acid-modified block copolymer is uniformly dispersed in the PVA resin cannot be obtained, and the mechanical properties of the resin tend to be lowered.
The weight average molecular weight of the acid-modified block copolymer is a value obtained by using gel permeation chromatography (GPC) and using polystyrene as a standard.

The melt viscosity of the acid-modified block copolymer at 220 ° C. and a shear rate of 122 sec ⁻¹ is usually 100 to 3000 mPa · s, preferably 300 to 2000 mPa · s, more preferably 800 to 1500 mPa · s. It is done.

  In the present embodiment, one type of acid-modified block copolymer may be used, but a plurality of types may be appropriately mixed for the purpose of obtaining desired characteristics.

  In the layered modeling support material, the acid-modified block copolymer is preferably contained at a ratio of 2 to 20 parts by mass with respect to 100 parts by mass of the PVA resin. By containing the acid-modified block copolymer in an amount of 2 parts by mass or more with respect to 100 parts by mass of the PVA-based resin, the suspended matter on the water surface during water dissolution can be reduced, and by making it 20 parts by mass or less. The stability of the melt viscosity of the composition can be maintained. The acid-modified block copolymer is more preferably 2 to 15 parts by mass, and still more preferably 5 to 10 parts by mass with respect to 100 parts by mass of the PVA resin.

  The additive for additive manufacturing of the present embodiment can contain other additives as long as the effects of the present invention are not impaired. Hereinafter, other components will be described.

  Since the support material for layered modeling is supplied to the head part of the layered modeling apparatus in a strand state, it is preferable that the layered modeling support material has an appropriate rigidity in consideration of the fact that the support material can be supplied smoothly. Further, when the strand-shaped support material is supplied to the head portion of the additive manufacturing apparatus, it may be supplied through the tube, and therefore, it is preferable that the inner surface of the tube and the surface of the support material have good slidability. . In order to smoothly supply the strand of the support material to the layered manufacturing apparatus to the head portion, it is preferable that the surface state of the support material is smooth and has no tackiness. In general, since the strand surface of the PVA-based resin is easy to absorb moisture and easily develops tackiness, it is preferable that the support material contains a filler so that the strand has appropriate rigidity and suppresses the tackiness of the strand. .

  As the filler, there are an organic filler and an inorganic filler, and an inorganic filler is preferable in terms of good thermal stability. Examples of inorganic fillers include oxides, hydroxides, carbonates, sulfates, silicates, nitrides, carbons, metals, etc., in that they do not adversely affect the thermal stability of the support material. Silicates are preferred. Examples of the silicate include calcium silicate, talc, clay, mica, montmorillonite, bentonite, activated clay, sepiolite, imogolite, serisalite, glass fiber, glass beads, silica-based balloon, etc. Talc is preferred in that smoothness is good and tackiness is reduced.

The particle size of the filler is preferably 0.5 to 500 μm, more preferably 50 to 400 μm, and still more preferably 100 to 300 μm. Furthermore, when using talc as a filler, the particle size of talc is preferably 0.5 to 10 μm, more preferably 1 to 5 μm, and still more preferably 2 to 3 μm. If these particle sizes are too small, kneading into the resin tends to be difficult, and if they are too large, they tend to cause surface roughness and a decrease in strength. Industrially, for example, “SG-95” and “SG-200” (both trade names) manufactured by Nippon Talc Co., Ltd., “LSM-400” (trade names) manufactured by Fuji Talc Industrial Co., Ltd., and the like are used. it can.
In addition, the particle size mentioned here refers to the particle diameter D50 measured by the laser diffraction method.

  The content of the filler is preferably 0 to 40% by mass, more preferably 2 to 30% by mass, and still more preferably 3 to 10% by mass in the support material for additive manufacturing. When the filler content is too small, the effect of blending the filler is not expressed, and when it is too much, the smoothness of the strand surface tends to be lowered or the flexibility tends to be lowered.

  In addition, a plasticizer may be blended in the support material, but the plasticizer content is preferably small in order to improve the molding stability of the support material for additive manufacturing in this embodiment. In the material, it is preferably 20% by mass or less, more preferably 10% by mass or less, further 1% by mass or less, and particularly preferably 0.1% by mass or less.

  In addition to the above components, known additives such as antioxidants, colorants, antistatic agents, ultraviolet absorbers, lubricants, and other thermoplastic resins can be appropriately blended. Other thermoplastic resins include, for example, linear low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer, ionomer, ethylene-propylene copolymer. , Ethylene-α-olefin (α-olefin having 4 to 20 carbon atoms) copolymer, ethylene-acrylic acid ester copolymer, polypropylene, propylene-α-olefin (α-olefin having 4 to 20 carbon atoms) copolymer Polyolefin resins in a broad sense such as polymers, polybutenes, polypentenes or other olefins alone or copolymers, polycyclic olefins, or those olefins alone or copolymers grafted with unsaturated carboxylic acids or esters thereof, Polystyrene resin, polyester, polyamide, copolymer polyamide Polyvinyl chloride, polyvinylidene chloride, acrylic resin, vinyl ester resin, polyurethane elastomer, chlorinated polyethylene, a thermoplastic resin such as chlorinated polypropylene.

(Method for producing support material for additive manufacturing)
In the present embodiment, the support material for additive manufacturing is prepared by, for example, mixing, heating, kneading in a molten state, extruding into a strand shape, cooling, and winding up on a reel. be able to.
Specifically, each component is premixed, or separately supplied to a single-screw or multi-screw extruder, heated, melted and kneaded, and the diameter is 1.5 to 3.0 mm from a single or multi-hole strand die. After being extruded into a strand and cooled and solidified by air cooling or water cooling, it is wound on a reel. The strand diameter must be stable, and it must be flexible and tough enough not to break even when wound on a reel, and rigid enough to be sent to the head without delay during additive manufacturing. It is.

(Manufacturing method of layered object and layered object)
A method for manufacturing a layered object using the layered modeling support material of the present embodiment will be described.
The additive manufacturing apparatus used for additive manufacturing may be a known one as long as it can perform additive manufacturing by heat melting having a plurality of heads that can extrude the model material and the support material, for example, create by Flash Forge. Dual head type additive manufacturing apparatuses such as Rayleigh Enterprise's Eagled, 3D Systems 'MBot Grid II and Stratasys' uPrint SE can be used.

  As a model material for forming a solid body, for example, various resins such as acrylonitrile / butadiene / styrene (ABS) resin, polylactic acid (PLA), polypropylene (PP), polystyrene, polyamide, and polyethylene have been studied. Polypropylene (PP) is mainly used from the viewpoints of thermal stability and mechanical properties after solidification, and the support material is required to have excellent adhesion to the polypropylene (PP).

  Similarly to the support material, the model material is also formed in a strand shape and wound around a reel. The strands of the model material and the support material are supplied to separate heads of the additive manufacturing apparatus, heated and melted by the head portions, and stacked in a fluid state so as to be pressed onto the stage from separate nozzles.

  The melting temperature at the head part is usually 150 to 220 ° C., extruded at a pressure of 200 to 1000 psi, and the lamination pitch is usually 200 to 350 μm.

  As described above, the laminate made of the support material and the model material is cooled and solidified, and then the support material is removed from the laminate to obtain the final shaped laminate model. For example, the support material of the present invention can be dissolved and removed with water. As the method for dissolving and removing, the support material may be dissolved and removed by immersing the laminate in water or warm water in a container, or the support material of the laminate may be washed away with running water. When the support material is dissolved and removed by immersing the laminate, it is preferable to stir or apply ultrasonic waves to shorten the dissolution and removal time, and the water temperature is preferably about 25 to 80 ° C. When the support material is dissolved and removed, about 10 to 10,000 times as much water or warm water as the weight of the support material is used. The support material of the present invention is also characterized by being easily dissolved and removed even at a relatively low temperature.

  EXAMPLES Hereinafter, although an Example and a comparative example further demonstrate this invention, this invention is not restrict | limited to the following example. In the examples, “parts” and “%” mean mass basis unless otherwise specified.

Example 1
(1) Production of PVA resin In a reaction can equipped with a reflux condenser, a dropping funnel, and a stirrer, 85 parts of vinyl acetate, 460 parts of methanol, and 7.6 parts of 3,4-diacetoxy-1-butene were charged. 0.32 parts of azobisisobutyronitrile was added, the temperature was raised under a nitrogen stream while stirring, and polymerization was started. Furthermore, 765 parts of vinyl acetate was dropped for 8 hours (dropping speed 95.6 parts / hour) 0.5 hours after the start of polymerization. 0.2 parts of azobisisobutyronitrile was added at 2.5 hours and 4.5 hours after the start of polymerization, and when the polymerization rate of vinyl acetate reached 85%, m-dinitrobenzene was added. The polymerization was terminated by adding a constant amount, and then, distillation was performed while blowing methanol vapor to remove unreacted vinyl acetate monomer out of the system to obtain a methanol solution of the copolymer.

  Next, the solution was diluted with methanol, adjusted to a solid content concentration of 50% by weight, charged into a kneader, and a 2% by weight methanol solution of sodium in sodium hydroxide was copolymerized while maintaining the solution temperature at 35 ° C. Saponification was carried out by adding 9 mmol to the total amount of vinyl acetate structural unit and 3,4-diacetoxy-1-butene structural unit in 1 mol. When saponification progresses and saponification precipitates and forms particles, a 2% by mass methanol solution is further added to 1 mol of the total amount of vinyl acetate structural units and 3,4-diacetoxy-1-butene structural units. 4 mmol was added and saponification was performed. Thereafter, 0.8 equivalent of sodium hydroxide was added to neutralizing acetic acid, filtered, washed thoroughly with methanol, dried in a hot air dryer, and PVA having a 1,2-diol structure in the side chain A resin (A) (hereinafter referred to as “PVA resin (A)”) was obtained.

The saponification degree of the obtained PVA-based resin (A) was 88 mol% when analyzed by the amount of alkali consumption required for hydrolysis of the residual vinyl acetate and 3,4-diacetoxy-1-butene structural unit in the resin. there were. The average degree of polymerization was 410 when analyzed in accordance with JIS K 6726.
Further, the content of the 1,2-diol structural unit represented by the formula (1) was measured by ¹ H-NMR (300 MHz proton NMR, d6-DMSO solution, internal standard substance: tetramethylsilane, 50 ° C.). The calculated value was 2 mol%.

(2) Production of Support Material 100 parts of the above PVA resin (A), 34 parts of maleic anhydride-modified polypropylene (“Admer QF500” (trade name) manufactured by Mitsui Chemicals, Inc.), styrene / carboxylic acid group-containing styrene / 8.6 parts of ethylene / butylene block copolymer (SEBS) (“Tough Tech M1943” (trade name) manufactured by Asahi Kasei Corporation, styrene content 20 mass%, acid value 10 mg CH ₃ ONa / g) were mixed and dry blended. . This was supplied to a twin-screw extruder, melt-kneaded under the following conditions, extruded into a strand having a diameter of 1.75 mm, air-cooled on a belt, wound on a reel, and a support material was obtained.
[Melting and kneading conditions]
Extruder: 15 mmφ L / D = 60, manufactured by Technobel Co., Ltd.
Extrusion temperature: C1 / C2 / C3 / C4 / C5 / C6 / C7 / C8 / D = 150/170/180/190/200/210/220/220/220 (° C.)
Rotation speed: 200rpm
Discharge rate: 1.5kg / h

(3) Evaluation of adhesiveness Support material (filament) and polypropylene model material (filament) obtained from 3D printer ("FDM-200HW-X" (trade name) manufactured by Ninjabot) ("PP Filament" manufactured by Verbatim) 1.75 mm-Transparent ”(trade name)) was set, and a molded article for evaluating adhesiveness was produced. A specific manufacturing method is as follows.
As shown in FIG. 1, first, on the platform 5 (modeling table), the first support material constituent parts 1, 1 ′, model material constituent parts 2, 2 ′, The support material constituent parts 3 of 2 were laminated in this order to produce a laminate. The first support material component 1 ′ and the model material component 2 ′ are portions that are finally removed from the laminate, and were manufactured with a resin filling rate (Infill) of 30%. Next, the laminate was peeled off from the platform 5, and the first support material component 1 ′ and the model material component 2 ′ were further peeled off to produce the adhesion evaluation shaped article 10.

The autograph ("AG-IS" (trade name) manufactured by Shimadzu Corporation) was used to evaluate the adhesion of the model material to the support material. Specifically, as shown in FIG. 2, the chuck is sandwiched between the protruding portion 1 a of the first support material constituting portion 1 and the protruding portion 2 a of the model material constituting portion 2 of the shaped article 10 for evaluating adhesiveness, and in the opposite direction. The peel strength when pulled at a speed of 5 mm / min was measured.
Similarly, the adhesion of the support material to the model material was evaluated. Specifically, as shown in FIG. 2, the chuck is sandwiched between the projecting portion 2 a of the model material constituting portion 2 and the projecting portion 3 a of the second support material constituting portion 3 of the model for adhesion evaluation 10, and in the opposite direction. The peel strength when pulled at a speed of 5 mm / min was measured.
Those having a peel strength of 350 N or more can be evaluated as having strong adhesive strength and excellent adhesiveness. In addition, when the support material and the model material were broken before the peeling of the bonded portion occurred at an adhesive strength of 350 N or more, it was evaluated as “material breakage”. The results are shown in Table 1.

(Example 2)
In Example 1, the amount of 3,4-diacetoxy-1-butene charged was 10 parts, the polymerization time was shortened, and the PVA resin (B) having a 1,2-diol structure in the side chain (hereinafter, “ PVA resin (B) ") was obtained.
The saponification degree of the obtained PVA-based resin (B) was 88 mol% when analyzed by the amount of alkali consumption required for hydrolysis of residual vinyl acetate and 3,4-diacetoxy-1-butene structural unit in the resin. there were. The average degree of polymerization was 390 when analyzed according to JIS K 6726.
Moreover, content of the 1, 2-diol structural unit represented by Formula (1) was 2.5 mol%.

  A support material was obtained in the same manner as in Example 1 using the PVA resin (B), and evaluated in the same manner. The results are shown in Table 1.

(Example 3)
100 parts of the PVA resin (B) obtained in Example 2 and 43 parts of maleic anhydride-modified polypropylene (“Admer QF500” (trade name) manufactured by Mitsui Chemicals, Inc.) were mixed and dry blended. This was supplied to a twin screw extruder, and a support material was obtained under the same conditions as in Example 1.
Evaluation was performed in the same manner as in Example 1 using the obtained support material. The results are shown in Table 1.

(Comparative Example 1)
100 parts of PVA resin (B) obtained in Example 2 and a styrene / ethylene / butylene block copolymer (SEBS) having a carboxylic acid group (“Tuftec M1943 / H1043 blend product” manufactured by Asahi Kasei Corporation) ), Styrene content 58% by mass, acid value 2 mg CH ₃ ONa / g) 43 parts were mixed and dry blended. This was supplied to a twin screw extruder, and a support material was obtained under the same conditions as in Example 1.
Evaluation was performed in the same manner as in Example 1 using the obtained support material. The results are shown in Table 1.

(Comparative Example 2)
In Example 1, the amount of 3,4-diacetoxy-1-butene charged was 13.6 parts, the polymerization time was shortened, and the PVA-based resin (C) having a 1,2-diol structure in the side chain (hereinafter referred to as “the polymerization time”) , "PVA resin (C)").
The saponification degree of the obtained PVA-based resin (C) was 88 mol% when analyzed by the residual vinyl acetate in the resin and the alkali consumption required for hydrolysis of 3,4-diacetoxy-1-butene structural units. there were. The average degree of polymerization was 350 when analyzed in accordance with JIS K 6726.
Moreover, content of the 1, 2-diol structural unit represented by Formula (1) was 3 mol%.

100 parts of the obtained PVA-based resin (C) and a styrene / ethylene / butylene block copolymer (SEBS) having a carboxylic acid group (“Tuftec M1911” (trade name) manufactured by Asahi Kasei Corporation, styrene content 30% by mass , Acid value 2 mg CH ₃ ONa / g) 43 parts were mixed and dry blended. This was supplied to a twin screw extruder, and a support material was obtained under the same conditions as in Example 1.
Evaluation was performed in the same manner as in Example 1 using the obtained support material. In the evaluation of adhesiveness, the second support material component did not adhere to the model material component. The results are shown in Table 1.

(Comparative Example 3)
Unmodified PVA resin (D) (hereinafter referred to as “PVA resin (D)”) was used.
The saponification degree of the PVA-based resin (D) was 72 mol% when analyzed by the alkali consumption required for hydrolysis of residual vinyl acetate and 3,4-diacetoxy-1-butene structural units in the resin. The average degree of polymerization was 550 when analyzed according to JIS K 6726.

PVA-based resin (D) was supplied to a twin screw extruder, and a support material was obtained under the same conditions as in Example 1.
Evaluation was performed in the same manner as in Example 1 using the obtained support material. In the evaluation of adhesiveness, neither the first support material component nor the second support material component was bonded to the model material component. The results are shown in Table 1.

  From the results of Table 1, in Examples 1 to 3, the adhesive strength of the model material constituent part to the support material constituent part and the adhesive strength of the support material constituent part to the model material constituent part are both 350 N or more. It was found that the support material 3 was excellent in adhesion with the model material.

DESCRIPTION OF SYMBOLS 1, 1 '1st support material structure part 2, 2' Model material structure part 3 2nd support material structure part 1a, 2a, 3a Protrusion part 5 Platform 10 Modeling object for adhesive evaluation

Claims (6)

  A support material for additive manufacturing comprising a polyvinyl alcohol resin and an acid-modified polyolefin resin.   The support material for additive manufacturing according to claim 1, wherein 10 to 80 parts by mass of the acid-modified polyolefin resin is contained with respect to 100 parts by mass of the polyvinyl alcohol resin.   The support material for additive manufacturing according to claim 1 or 2, further comprising an acid-modified block copolymer.   The support material for additive manufacturing according to claim 3, wherein the acid-modified block copolymer is contained in an amount of 2 to 20 parts by mass with respect to 100 parts by mass of the polyvinyl alcohol resin.   The layered modeling support material according to any one of claims 1 to 4, wherein the acid-modified polyolefin resin is an acid-modified polypropylene resin. The support material for additive manufacturing according to any one of claims 1 to 5, wherein the polyvinyl alcohol resin is a polyvinyl alcohol resin having a 1,2-diol structure in a side chain.

Images