CN103809379A - Back substrate for flexographic printing plate and manufacturing method thereof - Google Patents

Abstract

The present invention provides a back substrate for a flexographic printing plate and a method for manufacturing the same, wherein the method for manufacturing the same comprises the steps of: a flexible substrate is provided and an adhesive is coated on the flexible substrate. Wherein the adhesive comprises a resin, a photoinitiator and a photocurable compound, and then a first exposure step is performed to form an adhesive layer from the adhesive, wherein the conversion rate of unsaturated groups of the adhesive layer is between 10 and 65 percent. Also provided herein are back substrates made by the above-described methods.

Description

For back of the body substrate and the manufacture method thereof of flexographic printing version

Technical field

The invention relates to a kind of back of the body substrate and manufacture method thereof for flexographic printing version.

Background technology

Flexographic printing version comprises the photosensitive resin layer and back of the body substrate with relief pattern.Back of the body substrate comprises the following layer of ground and adhesion ground and photosensitive resin layer.Conventionally making after back of the body substrate, can form liquid photosensitive resin in following layer one side of back of the body substrate, then carrying out the exposure imaging processing procedure of liquid photosensitive resin, and form the photosensitive resin layer with relief pattern.Finally, the ground of flexographic printing version is attached on printing cylinder, so that photosensitive resin layer is fixed on printing cylinder.If Bonding strength and the permanance of following layer and ground and photosensitive resin interlayer are better, the serviceable life of flexographic printing version is longer.

U.S. Patent Bulletin discloses a kind of back of the body substrate for No. 3948666, and it comprises following layer and pliability ground.Solid is a kind of crosslinkable polyester polyurethane resin (polyester-polyurethane resin), and mat hydroxy and multifunctional isocyanate (polyfunctional isocyanante) wherein react and mutually follow on ground.But after coating solid, need at 40 to 80 ℃, react 40 to 120 hours, make the surface of formed following layer completely dry and comfortable.

U.S. Patent Bulletin discloses a kind of solid composition for No. 4269931.But after coating solid, still need at 120 ℃, carry out the baking of 2 hours, make the surface of formed following layer completely dry and comfortable.

U.S. Patent Bulletin discloses a kind of photosensitive resin element No. 5500327, comprises fid, thermmohardening layer and photo-hardening layer.The ultraviolet light that is 250 to 500nm by wavelength makes mutually to follow between thermmohardening layer and photo-hardening layer.But the time shutter too in short-term, the Bonding strength between thermmohardening layer and photo-hardening layer is lower, promotes its Bonding strength therefore need carry out time exposure.

In sum, need a kind of back of the body manufacture of substrates that shortens the processing procedure time, can make again Bonding strength and the permanance of following layer and ground and photosensitive resin interlayer good, and can overcome the problems referred to above.

Summary of the invention

An aspect of of the present present invention is to provide a kind of manufacture method of the back of the body substrate for flexographic printing version, and it comprises the following step: pliability ground is provided; Coating solid is on pliability ground, and wherein solid comprises resin, light initiator and photocurable compound, has at least two unsaturated groups in photocurable compound on every a part, and accounts for 5 to 30 percentage by weights (wt%) of solid gross weight; Carry out the first step of exposure, solid is irradiated to the first light source, to form following layer, and following layer is followed pliability ground.The conversion ratio of the unsaturated group of following layer is between 10 to 65%.

Another aspect of the present invention provides a kind of back of the body substrate being made by above-mentioned manufacture method.

Accompanying drawing explanation

For above and other object of the present invention, feature, advantage and embodiment can be become apparent, appended the description of the drawings is as follows:

Fig. 1 is the process flow diagram of demonstration according to the manufacture method of the flexographic printing version of an embodiment of the present invention;

Fig. 2 is the diagrammatic cross-section showing according to the back of the body substrate of an embodiment of the present invention;

Fig. 3 A-Fig. 3 C is the each process stage diagrammatic cross-section of demonstration according to the manufacture method of the flexographic printing version of an embodiment of the present invention.

[main element symbol description]

110,120,130,140,150: step

200: back of the body substrate

210: pliability ground

220: solid

225: following layer

300: flexographic printing version

310: liquid photosensitive resin layer

310 ': patterned shielding

310a: crosslink part

310b: uncrosslinked part

320: galley

Embodiment

Below will disclose multiple embodiment of the present invention with accompanying drawing, as clearly stated, the details on many embodiments will be explained in the following description.But, should be appreciated that, the details on these embodiments does not apply to limit the present invention.That is to say, in part embodiment of the present invention, these details are non-essential.In addition,, for the purpose of simplifying accompanying drawing, some known usual structures and element will illustrate in the mode of simply illustrating in the accompanying drawings.

Fig. 1 is the process flow diagram of demonstration according to the manufacture method of the flexographic printing version of an embodiment of the present invention.

In step 110, provide pliability ground 210, as shown in Figure 2.Pliability ground 210 is required to be the transparent material of light, with in post-exposure processing procedure, allows light pass through pliability ground 210, solid is reacted and with pliability ground 210 then.

In one embodiment, pliability ground 210 is the groups that select free polyethylene terephthalate (polyethylene terephthalate), polyester (polyester), polycarbonate (polycarbonate), polyolefin (polyolefin), polyamide (polyamide), polyacrylate (polyacrylate), Polyvinylchloride (polyvinylchloride), polystyrene (polystyrene) and composition thereof to form.

In one embodiment, for increasing Bonding strength, pliability ground 210 is done to surface treatment, surface treatment is as strong acid oxidation (oxidizing strong acid), corona discharge (corona discharge) or roughening processing.

In step 120, coating solid 220 is on pliability ground 210, as shown in Figure 2.Solid 220 comprises resin, light initiator and photocurable compound.For example can use line rod to carry out coating program, but be not limited to this.

Resin provides the flexibility of following layer, and it is the macromolecule that has unsaturated group or do not have unsaturated group.In one embodiment, resin accounts for this solid gross weight approximately 50 to 90wt%, is preferably and accounts for gross weight approximately 65 to 85wt%.In one embodiment, the weight average molecular weight of resin is 10000 to 90000.

In one embodiment, resin is the group that selects free acryl resin (acrylic resin), epoxy resin (epoxy resin), silicones (silicone resin), polyvinylformal (poly (vinyl formal)), polyvinyl butyral (poly-vinyl butyral, PVB), polyvinyl alcohol (PVA) (Polyvinyl alcohol), polyester (polyester), cellulose esters (cellulose esters) and composition thereof to form.

Light initiator carries out cross-linking reaction by photocurable compound.In one embodiment, light initiator account for this solid gross weight 3 to 25wt%, be preferably account for gross weight 5 to 20wt%.The light initiator of above-mentioned consumption can be accelerated unsaturated group in photocurable compound and carry out the speed of photopolymerization reaction.

In one embodiment, light initiator is to select free 1-hydroxy-cyclohexyl phenylacetone (1-hydroxycyclohexyl phenyl ketone), 2, 4, 6-trimethylbenzoyl-diphenyl phosphate oxidation (2, 4, 6-trimethylbenzoyldiphenylphosphine oxide), 2, 2-dimethoxy-2 phenyl acetophenone (2, 2-dimethoxy-2-phenylacetophenone), 2-isopropyl thia anthraquinone (2-isopropylthioxanthone), benzophenone (benzophenone), dibenzoyl peroxide (benzoylperoxide), 4-dimethylamino-ethyl benzoate (ethyl 4-dimethylaminobenzoate), 2-hydroxy-2-methyl-1-phenyl-1-acetone (2-hydroxy-2-methylpropiophenone), 4-benzoyl-4-methyl-diphenyl sulfide (4-(4-Methylphenylthio) benzophenone), the different monooctyl ester of 4 – dimethylaminobenzoic acid (2-Ethylhexyl 4-dimethylaminobenzoate), 2, 4-diethyl thiazolone (2, group 4-Diethylthioxantone) and composition thereof forming.

In photocurable compound, on every a part, have at least two unsaturated groups, be preferably and have 2 to 25 unsaturated groups, better is to have 3 to 20 unsaturated groups.Unsaturated group, in order to carry out photopolymerization reaction, follows solid 220 and pliability ground 210.

In the time that the unsaturated group number of photocurable compound is less than 2, after the first exposure-processed (being following step 130), by making, the conversion ratio of overall unsaturated group in photocurable compound is too high, cause residual unsaturated group number very little, by causing, the Bonding strength between solid and photosensitive resin layer is not good.In the time that the unsaturated group number of photocurable compound is greater than 25, after first exposure-processed (being following step 130) of identical energy, in photocurable compound, the conversion ratio of overall unsaturated group is on the low side, may affect the Bonding strength between solid and photosensitive resin interlayer or solid and pliability ground.

The percentage by weight that photocurable compound accounts for gross weight is 5 to 30wt%, is preferably the percentage by weight that accounts for gross weight and is 7 to 20wt%.If the addition of photocurable compound is less than 5%, the quantity of unsaturated group very little, causes Bonding strength variation.If the addition of photocurable compound is greater than 30%, can cause the not dry and comfortable and hard problem such as crisp of face, make to carry on the back substrate 200 and do not have a pliability.

In one embodiment, photocurable compound is acrylic monomer or acrylic acid series oligomer.In one embodiment, photocurable compound is to select free acrylate (acrylate), methyl acrylate (methyl acrylate), polyester acrylate (polyester acrylate), polyester acrylic methyl esters (polyester methacrylate), ammonia ester acrylate (urethane acrylate), ammonia ester methyl acrylate (urethane methacrylate), epoxy acrylate (epoxy acrylate), the group that epoxy radicals methyl acrylate (epoxy methacrylate) and composition thereof forms.

In addition, in the composition of solid, visual demand is further added a small amount of auxiliary agent, and as levelling agent, stabilizing agent or antioxidant, its content accounts for below the 5wt% of gross weight.

In step 130, carry out the first step of exposure, solid 220 is irradiated to the first light source, to form following layer 225, and then pliability ground 210 of following layer 225, as shown in Figure 2.Complete the making of carrying on the back substrate 200 at this.

The conversion ratio of the unsaturated group of following layer 225, between 10 to 65%, is preferably between 20 to 60%.If unsaturated group conversion ratio is less than 10%, the cross-linking density of following layer 225 is too low, causes Bonding strength poor.If unsaturated group conversion ratio is higher than 65%, the quantity of residual unsaturated group very little, causes Bonding strength variation.

In one embodiment, the first light source is ultraviolet light, visible ray, electron beam or X-ray.In one embodiment, carrying out the first step of exposure comprises take energy as 80mJ/cm ²to 200mJ/cm ²uV-irradiation solid.

In step 140, the exposing surface of following layer 225 is contacted to liquid photosensitive resin layer 310, as shown in Figure 3A.

Then, provide patterned shielding 310 ' in liquid photosensitive resin layer 310 top, cover liquid photosensitive resin layer 310 with part, as shown in Figure 3 B.

In step 150, carry out the second step of exposure, liquid towards photosensitive resin layer 310 and following layer 225 irradiate secondary light source, as shown in Figure 3 B.

In one embodiment, first carry out lower exposure manufacture process, then carry out upper exposure manufacture process.In lower exposure manufacture process, allow and carry out cross-linking reaction near the liquid photosensitive resin layer 310 of following layer 225 1 sides.In upper exposure manufacture process, allow and be not patterned the liquid photosensitive resin layer 310 that shielding layer 310 ' covers and carry out cross-linking reaction, do not react and be patterned the liquid photosensitive resin layer 310 that shielding layer 310 ' covers, and form crosslink part 310a and uncrosslinked part 310b, as shown in Figure 3 B.

In one embodiment, secondary light source is ultraviolet light, visible ray, electron beam or X-ray.In one embodiment, carry out the second step of exposure and comprise UV-irradiation liquid photosensitive resin layer 310 and the following layer 225 take wavelength as 320nm to 400nm.

Finally, remove uncrosslinked part 310b, to form flexographic printing version 300 as shown in Figure 3 C.For example can use sodium carbonate water or the uncrosslinked part 310b of suds eccysis.

To sum up, embodiments of the present invention can be passed through the first step of exposure, allow the unsaturated group of a part in solid carry out cross-linking reaction and to follow with ground, then carry out the second step of exposure, allow residual unsaturated group carry out cross-linking reaction and with liquid photosensitive resin layer then.Whereby, make the Bonding strength performance of following layer and ground and liquid photosensitive resin layer good.

And embodiments of the present invention only need to carry out exposure manufacture process and are cross-linked then reaction by unsaturated group, and do not need to use long thermal treatment processing procedure.Therefore, embodiments of the present invention have the effect of saving the energy, short processing procedure time and low equipment cost.

Another aspect of the present invention is that a kind of back of the body substrate 200 for flexographic printing version is being provided, and it comprises pliability ground 210 and following layer 225, as shown in Figure 2.Following layer 225 is positioned on pliability ground 210, and following layer 225 comprises resin, light initiator and photocurable polymkeric substance.Photocurable polymkeric substance is to be polymerized by photocurable compound.Resin, light initiator can be identical with above-mentioned embodiment with the embodiment of photocurable compound.

Embodiment

Following embodiment describes ad hoc fashion of the present invention in detail, and makes persond having ordinary knowledge in the technical field of the present invention be implemented the present invention, does not apply to limit the present invention.

Embodiment 1: the flexographic printing version of different photocurable compounds

The making flow process of the flexographic printing version of experimental example 1 to 6 is identical, and difference is only to use different photocurable compounds.The flow process that solid preparation, back of the body substrate manufacture and flexographic printing version are made is described below respectively.

solid preparation

Take experimental example 1 as example, the first toluene mixed dissolution in advance with 30g by the polyvinyl butyral of 15g (trade name: B03-HX, source: Changchun petrochemistry).Then, add the photocurable Compound D OUBLEMER 588 of 2g, then add light initiator 1-hydroxy-cyclohexyl phenylacetone (trade name: IR-184, the source: Ciba)/30g MEK of the 1.25g dissolving in advance.Experimental example 2 to 6 is also prepared solid with the part by weight that is same as experimental example 1, then carries out the making flow process of following back of the body substrate and flexographic printing version.Composition and the source thereof of the photocurable compound of experimental example 1 to 6 please refer to table one.

Table one

back of the body substrate manufacture

Above-mentioned solid is applied on the PET film of 125 micron thickness with line rod, and tests the infrared spectrum of solid.Then with 100 ℃ of bakings of baking oven 3 minutes, allow solvent volatilize completely.Subsequently, the PET film that scribbles solid is placed in to treatment with ultraviolet light machine (Fusion F300S UV system), (ultraviolet light energy is as 80mJ/cm to carry out exposure program in travelling belt mode ²), produce the back of the body substrate with following layer.UV fluorescent tube is the electrodeless formula fluorescent tube of Fusion H type, and UV energy can be set as 40-350mJ/cm ².The thickness of the following layer forming is 10 ± 2 microns.And then this following layer is done to hundred lattice tests and infrared spectrum test.

Hundred lattice tests are according to ASTM D3359, test the Bonding strength between following layer and ground with hundred lattice cuttves and 3M adhesive tape.First, cut out crossed grid figure with hundred lattice cuttves on following layer, notch depth is until ground.Then one end of test tape is fixed in hand, the other end is attached to the surface of wish test, and to point the removal bubble of exerting pressure.Again certain one end of the adhesive tape posting is torn up and hold with finger folder, draw rapidly except adhesive tape with the angle of approximately 90 ° immediately.Finally, on visual examination adhesive tape, whether there is the coating substance being stuck, and judge grade according to table two.

Table two

Unsaturated group conversion ratio be (after coating before baking) before comparison treatment with ultraviolet light with treatment with ultraviolet light after the variation of unsaturated group.Its account form is as following formula (1).

$\mathrm{Conversion}\%=[1-(\frac{B2}{B1}\×\frac{A1}{A})]\×100\%$

A1: 1713cm before treatment with ultraviolet light ^-1(C=O) absorption peak height

A2: 1713cm after treatment with ultraviolet light ^-1(C=O) absorption peak height

B1: 1410cm before treatment with ultraviolet light ^-1(C=C) absorption peak height

B2: 1410cm after treatment with ultraviolet light ^-1(C=C) absorption peak height

flexographic printing version is made

In the present embodiment, be that making thickness is the galley of 3.94 millimeters.First on exposure bench, place egative film, more sequentially cover one deck by overlay film and coating one deck liquid photosensitive resin (material model: MacDermid 36R).Then the following layer of back of the body substrate is covered to soft version photosensitive resin, expose (fluorescent tube model: PHILIPS TK40W/10R), and form crosslink part and uncrosslinked part.Tear after this stack material, wash uncrosslinked part off with sodium carbonate (sodium carbonate) aqueous solution of 1-3%, form the photosensitive resin layer with relief pattern.Carry out again the UV-A exposure of 20 minutes, then with 60 ℃ of bakings of baking oven 30 minutes.Finally carry out again UV-C exposure 5 minutes, make flexographic printing version.Then this flexographic printing version is done to Bonding strength test.

Bonding strength test is to use ballpoint pen (classmate's board, nib is 0.5mm, Taiwan system) to scrape flexographic printing version with 45 °, then judges grade according to table three.

Table three

The test result of above-mentioned back of the body substrate and flexographic printing version is arranged as shown in Table 4.

Table four

As shown in Table 4, under the first exposure-processed of identical ultraviolet light energy, use different photocurable compounds to cause obvious impact to Bonding strength.In the time that the unsaturated group number of every a part of photocurable compound is less than 3, after treatment with ultraviolet light, the conversion ratio of unsaturated group is higher, and residual unsaturated group is reduced, and causes Bonding strength to decline.Therefore, the unsaturated group number of photocurable compound is preferably and is greater than 3.

Embodiment 2: the flexographic printing version of the photocurable compound of different content

The making flow process of the flexographic printing version of experimental example 7 to 11 is identical with experimental example 1, and difference is to add the photocurable Compound D OUBLEMER 588 of Different Weight ratio.Finally, the Bonding strength of the flexographic printing version of test experiments example 7 to 11, please refer to table five.

Table five

From table five result, the addition of photocurable compound can have a strong impact on the Bonding strength between galley and following layer.The addition of photocurable compound is better between 7 to 20%.If the addition of photocurable compound is less than 7%, the quantity of unsaturated group very little, causes Bonding strength variation.If the addition of photocurable compound is greater than 20%, can cause face not dry and comfortable and firmly crisp, make to carry on the back substrate and do not have a pliability, and Bonding strength variation between galley and following layer.

Embodiment 3: the flexographic printing version of different ultraviolet light energy process

The formula of the solid of experimental example 12 to 18 is identical with experimental example 1, and difference is to carry out the first exposure manufacture process with different ultraviolet light energy.Finally, the Bonding strength of the flexographic printing version of test experiments example 12 to 18 and permanance (through hot and humid Bonding strength test after treatment), please refer to table six.

Durability test is that above-mentioned adagio printed panel is positioned in hot and humid (60 ℃, 90RH%) baking oven to 336 hours, does Bonding strength test after to be removed.Similarly, judge the grade of Bonding strength according to table three.

Table six

Table six shows, in the time that ultraviolet light energy is higher, the unsaturated group conversion ratio of photocurable compound also just promotes thereupon.When unsaturated group conversion ratio is between 20 to 60% time, the Bonding strength between galley and following layer is better.In addition,, along with unsaturated group conversion ratio is higher, permanance is also better.Supposition is because the crosslinking degree of following layer is higher, can reduce the impact on following layer of temperature or humidity, makes aqueous vapor be difficult for entering in following layer, destroys the bond intensity between galley and following layer.If but unsaturated group conversion ratio is higher than 60%, is preparing after back of the body substrate, the quantity of residual unsaturated group very little, causes Bonding strength variation.

Although the present invention discloses as above with embodiment; so it is not in order to limit the present invention; anyly be familiar with this skill person; without departing from the spirit and scope of the present invention; when being used for a variety of modifications and variations, the scope that therefore protection scope of the present invention ought define depending on appending claims is as the criterion.

Claims (15)

1. A method for manufacturing a back substrate for a flexographic printing plate, comprising: providing a flexible substrate; Coating an adhesive on the flexible substrate, wherein the adhesive includes: resin; photoinitiators; and A photocurable compound having at least two unsaturated groups and accounting for 5 to 30 weight percent of the total weight of the adhesive; performing a first exposure step, irradiating a first light source to the adhesive to form an adhesive layer, and the adhesive layer is attached to the flexible substrate; Wherein performing the first exposure step includes making the conversion rate of the unsaturated group of the following layer between 10% and 65%. 2 . The method for manufacturing a back substrate for a flexographic printing plate according to claim 1 , wherein the photocurable compound has 2 to 25 unsaturated groups. 3 . The method for manufacturing a back substrate for a flexographic printing plate according to claim 1 , wherein the photocurable compound is an acrylic monomer or an acrylic oligomer. 4. The method for manufacturing a back substrate for a flexographic printing plate according to claim 1, wherein the photocurable compound is selected from the group consisting of acrylate, methyl acrylate, polyester acrylate, polyester methyl acrylate The group consisting of urethane acrylate, urethane acrylate, epoxy acrylate, epoxy methyl acrylate, and mixtures thereof. 5. The method for manufacturing a back substrate for a flexographic printing plate according to claim 1, wherein the photoinitiator is selected from 1-hydroxycyclohexyl phenylacetone, 2,4,6-tri Tolyl-diphenylphosphine oxide, 2,2-dimethoxy-2-phenylacetophenone, 2-isopropylthioxanthraquinone, benzophenone, dibenzoyl peroxide, 4-Dimethylamino-ethyl benzoate, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 4-benzoyl-4-methyl-diphenylsulfide, 4-dimethylamino The group consisting of isooctyl benzoate, 2,4-diethylthiazolone and mixtures thereof. 6 . The method for manufacturing a back substrate for a flexographic printing plate according to claim 1 , wherein the photoinitiator accounts for 3 to 25 weight percent of the total weight of the adhesive. 7 . 7. The method for manufacturing a back substrate for a flexographic printing plate according to claim 1, wherein the resin is selected from acrylic resin, epoxy resin, silicone resin, polyvinyl formal, polyvinyl acetal The group consisting of butyraldehyde, polyvinyl alcohol, polyester, cellulose ester and mixtures thereof. 8 . The method for manufacturing a back substrate for a flexographic printing plate according to claim 1 , wherein the first light source is ultraviolet light, visible light, electron beam or X-ray. 9. The method for manufacturing ^a back ^substrate for a flexographic printing plate according to claim 1, wherein performing the first exposure step comprises irradiating the Adhesive. 10. The method for manufacturing a back substrate for a flexographic printing plate according to claim 1, further comprising: contacting the exposed surface of the adhesive layer with a liquid photosensitive resin layer; and providing a patterned masking layer above the liquid photosensitive resin layer to partially cover the liquid photosensitive resin layer; and A second exposure step is carried out to irradiate the liquid photosensitive resin layer and the adhesive layer with a second light source, so that the adhesive layer is bonded to the liquid photosensitive resin layer. 11. The method for manufacturing a back substrate for a flexographic printing plate according to claim 10, wherein the second light source is ultraviolet light, visible light, electron beam or X-ray. 12. The method for manufacturing a back substrate for a flexographic printing plate according to claim 10, wherein performing the second exposure step comprises irradiating the liquid photosensitive resin layer and the liquid photosensitive resin layer with ultraviolet light having a wavelength of 320 nm to 400 nm. Next layer. 13. The method for manufacturing a back substrate for a flexographic printing plate according to claim 10, wherein performing the second exposure step comprises forming a crosslinked part and an uncrosslinked part in the liquid photosensitive resin layer . 14. The method for manufacturing a back substrate for a flexographic printing plate according to claim 1, wherein the material of the flexible substrate is selected from polyethylene terephthalate, polyester, polyester The group consisting of carbonates, polyolefins, polyamides, polyolefin resins, polyacrylates, polyvinyl chloride, polystyrene, and mixtures thereof. 15. A back substrate for a flexographic printing plate, characterized in that it is manufactured by the manufacturing method according to any one of claims 1 to 14.

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