Background
The protective film is composed of an adhesive layer and a substrate, and is a film for protecting a vulnerable surface, and the purpose of the protective film is to temporarily protect the surface of the protected substrate during production, processing, transportation and storage. The main performance requirements of the industry for protective films are: proper and stable viscosity, easy uncoiling, few crystal points, easy tearing, no residual glue, no image, weather resistance and the like.
The adhesive resin is the core raw material of the protective film and determines the main performance of the product. The protective film product is generally in a roll form, and the adhesive layer of the protective film and the backing layer are in close contact to generate a strong adhesive tension, and a certain force is required to separate the protective film product in use, which is known as unwinding force. The uncoiling performance is an important performance of the protective film, the downstream use and the performance of the protective film are influenced, the uncoiling force required by the protective film which is difficult to uncoil is large, and the labor intensity of a user is increased; in addition, the surface of the protective film is uneven due to a trace line when unwinding is stopped, the tensile strain of the protective film is high due to difficult unwinding, the tendency of rebound and edge shrinkage on the substrate is high, and the effect is greater for a thin protective film. In addition, for some surface roughened or difficult-to-stick substrates, the protective film has an increased content of an adhesive layer, resulting in increased tackiness and thus more difficult unwinding.
Currently, studies on protective films have been focused mainly on one of the properties such as weather resistance, peel strength, and small crystal grain size, and there is no solution concerning unwinding properties or simultaneously solving a plurality of performance problems.
In view of the above, the present invention is particularly proposed.
Disclosure of Invention
The first purpose of the present invention is to provide a viscous resin to solve the technical problems of the prior art that the viscous resin cannot achieve the compatibility of viscosity, uncoiling property, weather resistance, few crystal points, etc.
The second purpose of the invention is to provide a preparation method of the viscous resin, which is simple to operate and mild in conditions.
The third purpose of the invention is to provide a protective film, wherein an adhesive layer of the protective film is prepared from adhesive resin, and the protective film has the characteristics of high viscosity, easiness in uncoiling, stable peeling force, few crystal points, good weather resistance and the like.
In order to achieve the above purpose of the present invention, the following technical solutions are adopted:
the adhesive resin comprises the following components in parts by weight:
45-72 parts of hydrogenated styrene block copolymer, 5-25 parts of acrylic block copolymer, 20-40 parts of tackifying resin, 3-10 parts of plasticizer and 0.1-0.5 part of antioxidant;
the acrylic block copolymer is a living anionic polymer elastomer.
In a specific embodiment of the present invention, the acryl block copolymer includes an acrylate copolymer in a-B-a form and/or a-B form.
In a specific embodiment of the present invention, the acrylic block copolymer is a triblock copolymer of a-B-a type, wherein block a is PMMA and block B is PBA or P (BA/2 EHA).
In a specific embodiment of the present invention, the hydrogenated styrene block copolymer comprises at least two of SEBS, SEPS, and SEP.
In a specific embodiment of the invention, the content of the styrene block in the SEBS is 8-20%; the content of the styrene block in the SEPS is 15-40 percent; the content of the styrene block in the SEP is 15-50%.
In a specific embodiment of the invention, in the SEBS, the 1, 2-addition degree in the polybutadiene block precursor is 60-85% by mole; in the SEBS, the content of the diblock is 0-15%.
In a specific embodiment of the invention, the melt flow index of the SEBS is 1-15 g/10 min. The melt flow index was measured at a temperature of 230 ℃ under a load of 2.16 kg.
In a specific embodiment of the present invention, the SEPS has a melt flow index of 1 to 15g/10 min. The melt flow index was measured at a temperature of 230 ℃ under a load of 2.16 kg.
In a particular embodiment of the invention, the SEP has a melt flow index of < 2g/10 min. The melt flow index was measured at a temperature of 230 ℃ under a load of 2.16 kg.
In a specific embodiment of the invention, the melt flow index of the acrylic block copolymer is 3-10 g/10 min. The melt flow index was measured at a temperature of 190 ℃ under a load of 2.16 kg.
In a specific embodiment of the invention, the tackifying resins include low softening point tackifying resins and high softening point tackifying resins; the softening point of the low-softening-point tackifying resin is 100-135 ℃; the softening point of the tackifying resin with high softening point is 135-160 ℃.
In a specific embodiment of the present invention, the mass ratio of the low-softening-point tackifying resin to the high-softening-point tackifying resin is (2 to 6): 1.
In a specific embodiment of the present invention, the tackifying resin comprises at least two of hydrogenated carbon five petroleum resin, hydrogenated carbon nine petroleum resin, hydrogenated carbon five-carbon nine copolymerized petroleum resin, terpene resin, modified terpene resin, hydrogenated rosin, and pure monomer resin.
In a specific embodiment of the present invention, the plasticizer includes any one or more of paraffin oil, naphthenic oil, and polybutene.
In a specific embodiment of the present invention, the antioxidant includes any one or more of pentaerythritol tetrakis [ β - (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] (antioxidant 1010), diethylene glycol bis [ β - (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate ] (antioxidant 245), thioethylene-diethylene bis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] (antioxidant 1035), tris (2, 4-di-tert-butylphenyl) phosphite (antioxidant 168), and pentaerythritol tetrakis (3-laurylthiopropionate) (412S).
The invention also provides a preparation method of the adhesive resin, which comprises the following steps:
and extruding and granulating a mixture obtained by mixing the components in proportion by a double screw.
In a particular embodiment of the invention, the preparation of the mixture comprises: the hydrogenated styrene block copolymer and the plasticizer are uniformly mixed, and then the mixture is mixed with the acrylic block copolymer, the tackifying resin and the antioxidant to obtain a mixture.
In a specific embodiment of the present invention, the temperature for mixing the hydrogenated styrene block copolymer and the plasticizer is 55 to 65 ℃ and the mixing time is 3 to 10 min. In actual operation, after mixing, standing at room temperature for 24h, and mixing with acrylic block copolymer and the like.
The invention also provides a protective film comprising an adhesive layer made of any one of the adhesive resins described above.
In a specific embodiment of the invention, the protective film further comprises a core layer and an outer surface layer, and the adhesive layer, the core layer and the outer surface layer are attached in sequence.
In a specific embodiment of the present invention, the core layer and the outer skin layer are both made of polyethylene.
In actual operation, the protective film is prepared in a three-layer co-extrusion film blowing mode.
Compared with the prior art, the invention has the beneficial effects that:
(1) the adhesive resin disclosed by the invention adopts the hydrogenated styrene block copolymer and a certain tackifying resin, does not contain unsaturated double bonds, and has good stability and aging resistance; meanwhile, the acrylic block copolymer has higher polarity, can increase the physical adsorption of the viscous resin on the base material, and improve the stripping force;
(2) the adhesive resin can be used for preparing self-adhesive protective films, and has the advantages of high viscosity, easiness in uncoiling, stable stripping force, few crystal points and good weather resistance;
(3) the preparation method of the viscous resin is simple to operate, mild in condition, free of volatile solvent in the components and free of environmental pollution in the production process.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the following detailed description, but those skilled in the art will understand that the following described examples are some, not all, of the examples of the present invention, and are only used for illustrating the present invention, and should not be construed as limiting the scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
The adhesive resin comprises the following components in parts by weight:
45-72 parts of hydrogenated styrene block copolymer, 5-25 parts of acrylic block copolymer, 20-40 parts of tackifying resin, 3-10 parts of plasticizer and 0.1-0.5 part of antioxidant;
the acrylic block copolymer is a living anionic polymer elastomer.
As in the various embodiments, the hydrogenated styrenic block copolymer may be used in amounts of 45 parts, 48 parts, 50 parts, 52 parts, 55 parts, 58 parts, 60 parts, 62 parts, 65 parts, 68 parts, 70 parts, 72 parts, and the like; the acrylic block copolymer may be used in amounts of 5 parts, 8 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, and the like; tackifying resins can be used in amounts of 20 parts, 22 parts, 25 parts, 28 parts, 30 parts, 32 parts, 35 parts, 38 parts, 40 parts, and the like; the plasticizer may be used in amounts of 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, and the like; the antioxidant may be used in an amount of 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, etc.
In a specific embodiment of the present invention, the acryl block copolymer includes an acrylate copolymer in a-B-a form and/or a-B form.
In a specific embodiment of the present invention, the acrylic block copolymer is a triblock copolymer of a-B-a type, wherein block a is PMMA and block B is PBA or P (BA/2 EHA).
In a specific embodiment of the present invention, the hydrogenated styrene block copolymer comprises at least two of SEBS, SEPS, and SEP.
In a specific embodiment of the present invention, the content of the styrene block in the SEBS is 8% to 20%, preferably 10% to 15%; the content of the styrene block in the SEPS is 15-40%, preferably 17-30%; the content of the styrene block in the SEP is 15-50%, preferably 20-40%. In the present invention, the content of each block is not additionally described, and is calculated by weight percent (wt%).
As in various embodiments, the styrene block content of the SEBS can be 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, etc.; the styrene block content in the SEPS may be 15%, 17%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, etc.; the styrene block content in the SEP may be 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 37%, 38%, 40%, 42%, 45%, 48%, 50%, etc.
In a specific embodiment of the invention, in the SEBS, the 1, 2-addition degree in the polybutadiene block precursor is 60-85% by mole; in the SEBS, the content of the diblock is 0-15%.
As in various embodiments, the degree of 1, 2-addition in the polybutadiene block precursor (i.e., the amount of B in the EB segment of the hydrogenated SEBS) in the SEBS may be 60%, 65%, 70%, 75%, 80%, 85%, etc., on a molar basis; the content influences the viscoelasticity and the glass transition temperature, the content is within the range, the softening effect can be achieved, and the performances of high peel strength, few crystal points, heat resistance and the like of the adhesive resin are realized by matching with other components. The SEBS is optional, and may be present in an amount of 0%, 1%, 5%, 7%, 8%, 10%, 12%, 15%, or the like.
In a specific embodiment of the invention, the melt flow index of the SEBS is 1-15 g/10min, preferably 2-10 g/10 min. The melt flow index was measured at a temperature of 230 ℃ under a load of 2.16 kg.
As in various embodiments, the melt flow index of the SEBS can be 1g/10min, 2g/10min, 3g/10min, 3.5g/10min, 4g/10min, 4.5g/10min, 5g/10min, 8g/10min, 10g/10min, 12g/10min, 15g/10min, and the like.
In a specific embodiment of the present invention, the melt flow index of the SEPS is 1 to 15g/10min, preferably 2 to 10g/10 min. The melt flow index was measured at a temperature of 230 ℃ under a load of 2.16 kg.
As in various embodiments, the SEPS may have a melt flow index of 1g/10min, 2g/10min, 3g/10min, 5g/10min, 8g/10min, 10g/10min, 12g/10min, 15g/10min, and so forth.
In a particular embodiment of the invention, the SEP has a melt flow index of < 2g/10 min. The melt flow index was measured at a temperature of 230 ℃ under a load of 2.16 kg.
As in various embodiments, the SEP may have a melt flow index of < 2g/10min, < 1g/10min, more preferably < 0.5g/10 min.
In a specific embodiment of the invention, the melt flow index of the acrylic block copolymer is 3-10 g/10 min. The melt flow index was measured at a temperature of 190 ℃ under a load of 2.16 kg. Wherein the acrylic block copolymer is a living anionic polymer elastomer. For example, the hard block A is PMMA, and the soft block B is an A-B-A triblock copolymer (MAM for short) of PBA.
As in various embodiments, the acrylic block copolymer can have a melt flow index of 3g/10min, 4g/10min, 5g/10min, 6g/10min, 7g/10min, 8g/10min, 9g/10min, 10g/10min, and the like.
In a specific embodiment of the invention, the tackifying resins include low softening point tackifying resins and high softening point tackifying resins; the softening point of the low-softening-point tackifying resin is 100-135 ℃; the softening point of the tackifying resin with high softening point is 135-160 ℃.
In a specific embodiment of the present invention, the mass ratio of the low-softening-point tackifying resin to the high-softening-point tackifying resin is (2 to 6): 1.
As in the different embodiments, the mass ratio of the low and high softening point tackifying resins can be 2: 1, 3: 1, 4: 1, 5: 1, 6: 1, etc.
In a specific embodiment of the present invention, the tackifying resin comprises at least two of hydrogenated carbon five petroleum resin, hydrogenated carbon nine petroleum resin, hydrogenated carbon five-carbon nine copolymerized petroleum resin, terpene resin, modified terpene resin, hydrogenated rosin, and pure monomer resin.
As in the various embodiments, the tackifying resins may include hydrogenated carbon five petroleum resins and hydrogenated carbon nine petroleum resins, may also include hydrogenated carbon nine petroleum resins and pure monomer resins, may also include terpene resins and pure monomer resins, may also include hydrogenated carbon five-carbon nine copolymerized petroleum resins and terpene resins, and the like. The tackifying resins may be two types of tackifying resins having different softening points in the same type of tackifying resin, and may be classified into a low softening point tackifying resin and a high softening point tackifying resin defined in the above description.
In a specific embodiment of the present invention, the plasticizer includes any one or more of paraffin oil, naphthenic oil, and polybutene.
In a specific embodiment of the present invention, the antioxidant includes any one or more of pentaerythritol tetrakis [ β - (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] (antioxidant 1010), diethylene glycol bis [ β - (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate ] (antioxidant 245), thioethylene-diethylene bis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] (antioxidant 1035), tris (2, 4-di-tert-butylphenyl) phosphite (antioxidant 168), and pentaerythritol tetrakis (3-laurylthiopropionate) (412S).
The invention also provides a preparation method of the adhesive resin, which comprises the following steps:
and extruding and granulating a mixture obtained by mixing the components in proportion by a double screw. In practical operation, the length-diameter ratio of the twin screw can be 48: 1; the temperature of the twin screw extrusion may be from 150 ℃ to 180 ℃, e.g. 180 ℃.
In a particular embodiment of the invention, the preparation of the mixture comprises: the hydrogenated styrene block copolymer and the plasticizer are uniformly mixed, and then the mixture is mixed with the acrylic block copolymer, the tackifying resin and the antioxidant to obtain a mixture.
In a specific embodiment of the present invention, the temperature for mixing the hydrogenated styrene block copolymer and the plasticizer is 55 to 65 ℃ and the mixing time is 3 to 10 min. In actual operation, after mixing, standing at room temperature for 24h, and mixing with acrylic block copolymer and the like.
The invention also provides a protective film comprising an adhesive layer made of any one of the adhesive resins described above.
In a specific embodiment of the invention, the protective film further comprises a core layer and an outer surface layer, and the adhesive layer, the core layer and the outer surface layer are attached in sequence.
In a specific embodiment of the present invention, the core layer and the outer skin layer are both made of polyethylene.
In actual operation, the protective film is prepared in a three-layer co-extrusion film blowing mode.
Example 1
This example provides a method for preparing an adhesive resin, comprising the steps of:
(1) mixing the hydrogenated styrene block copolymer and the plasticizer at a high speed for 5min at 60 ℃, standing at room temperature for 24h, and uniformly mixing with the acrylic block copolymer, the tackifying resin and the antioxidant to obtain a mixture;
(2) adding the mixture obtained in the step (1) into a double-screw extruder for extrusion, granulating under low-temperature water containing an anti-sticking emulsion auxiliary agent (such as organosilicone emulsion, Dow Corning (Dow's organosilicon) BY22-751), and drying; the extrusion conditions of the twin-screw extruder include: the length-diameter ratio is 48: 1 and the temperature is 180 ℃.
Wherein the raw materials are respectively as follows in parts by weight:
47 parts of SEBS, 6 parts of SEP, 4 parts of paraffin oil, 10 parts of acrylic block copolymer MAM (Cola LA3320), 25 parts of hydrogenated petroleum resin, 8 parts of pure monomer resin and 10100.3 parts of antioxidant.
In the SEBS, the content of a styrene block is 13 wt%, the addition degree of 1,2 in a polybutadiene block precursor is 75% in terms of mole number, and the content of a diblock is 7 wt%. The melt flow index of the SEBS is 3.5g/10min (230 ℃, 2.16 kg).
In the SEP, the styrene block content was 37 wt.%. The SEP has a melt flow index of < 0.5g/10min (230 ℃ C., 2.16 kg).
The hydrogenated petroleum resin is hydrogenated carbon nine petroleum resin, and the softening point of the hydrogenated petroleum resin is 125 ℃; the pure monomer resin had a softening point of 140 ℃.
The melt flow index of the acrylic block copolymer is 6.2g/10min (190 ℃, 2.16 kg).
Examples 2 to 4
The adhesive resins of examples 2 to 4 were prepared by referring to example 1 except that the kinds and/or amounts of some of the raw materials were different. The specific amounts and kinds of the raw materials of examples 2 to 4, etc. are shown in tables 1 and 2.
TABLE 1 raw material information for examples 2-4
Wherein, the antioxidant 1010 can be replaced by any one or more of the antioxidant 245, the antioxidant 1035, the antioxidant 168 and the antioxidant 412S.
Table 2 raw material composition characterization parameters for examples 2-4
Wherein "-" in Table 2 means that the substance was not added in the corresponding examples, and thus the composition characteristic parameters were not shown.
Examples 5 to 8
Examples 5-8 each provide a protective film, which is prepared by a method comprising the steps of:
the adhesive resin is an inner-layer adhesive raw material of the protective film, the polyethylene is used as a middle-layer raw material (a core layer) and an outer-layer raw material (an outer surface layer), the three-layer co-extrusion film blowing (the temperature of the adhesive layer of the film blowing machine is 160 ℃ and the temperature of the polyethylene layer is 170 ℃) is carried out, and the self-adhesive protective film is obtained by cooling and rolling. The total thickness of the protective film and the thickness of the adhesive layer, the core layer and the outer surface layer are the same. Specifically, the adhesive layer thickness was 4 μm, and the core layer thickness and the outer layer thickness were each 23 μm.
In the protective films of examples 5 to 8, adhesive layers were prepared using the adhesive resins of examples 1 to 4 as inner layer materials, respectively.
Comparative examples 1 to 3
Comparative examples 1 and 3 are the adhesive resins prepared by the process of example 1, except that the types and/or amounts of some of the raw materials are different. The method for preparing the tackifying resin of comparative example 2 comprises: all raw materials were blended at room temperature for 2min and then fed and extruded (extrusion conditions were the same as in example 1).
The specific amounts and kinds of the raw materials used in comparative examples 1 to 3 are shown in tables 3 and 4.
TABLE 3 raw material information of comparative examples 1 to 3
TABLE 4 raw Material composition characterization parameters of comparative examples 1 to 3
In table 4, "-" means that the substance was not added in the corresponding examples, and thus the composition characteristic parameters were not shown.
Comparative examples 4 to 6
Comparative examples 4 to 6 each provide a protective film, the production method of which is referred to that of examples 5 to 8 except that: the adhesive resins are different. In the protective films of comparative examples 4 to 6, adhesive layers were produced using the adhesive resins of comparative examples 1 to 3 as inner layer materials, respectively.
Experimental example 1
To illustrate the properties of the tackifying resins obtained in the different examples and comparative examples of the invention, the melt index, hardness and mechanical properties of the tackifying resins obtained in examples 1 to 4 and comparative examples 1 to 3 were determined according to GB/T3682, GB/T2411 and GB/528, respectively. The test results are shown in Table 5 (in which the adhesive resin pellets obtained by pelletizing the respective examples and comparative examples were tested; mechanical property test specimens were in the form of 2mm thick die-cut dumbbells with a drawing rate of 500 mm/min).
TABLE 5 Performance test results for different tackifying resins
Experimental example 2
In order to comparatively illustrate the properties of the protective films obtained in the different examples and comparative examples of the present invention, the properties of the protective films obtained in examples 5 to 8 and comparative examples 4 to 6 were measured, and the test items and methods were as follows.
And (3) testing the peel strength: testing the peel strength of the protective film and the base material after being attached for 20min at room temperature, 168h at room temperature and after being thermally aged at 75 ℃ according to GB/T2792 (the thickness of an adhesive layer is 4 mu m in a peel force test, and the thicknesses of a core layer and an outer layer are 23 mu m thick LDPE films respectively); and observing and recording the phenomenon change of the substrate surface after the heat aging at 75 ℃, and the test result is shown in table 6.
And (3) unwinding force test: two 25mm wide samples of protective film (same thickness as before) were laminated together on a standard steel plate and then roll laminated using a 2kg standard roller at 300 mm/min. The upper film was peeled off a section from the lower film and then tested according to the 180 ° peel strength test method of GB/T2792, recording the maximum as the unwind force, the test results are shown in table 7.
Table 6 peel strength test results for different protective films
Table 7 unwinding force test results for different protective films
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.