UV (ultraviolet) viscosity-reducing adhesive tape for PCB (printed circuit board) substrate cutting process and preparation method of UV viscosity-reducing adhesive tape

Abstract

The invention relates to the technical field of adhesives, in particular to a UV viscosity-reducing adhesive tape for a PCB substrate cutting process and a preparation method of the UV viscosity-reducing adhesive tape. The method comprises: preparing a cured adhesive tape; detecting the peel strength; judging according to the peel strength, judging according to the area of the residual adhesive when the use standard is met, determining a reason when the use standard is not met according to the preliminary judgment, and determining the reason which does not meet the use standard according to the surface dust concentration when the use standard is not met according to the judgment; when it is judged that the current formula has problems, a formula changing notice is sent out; when it is judged that preparation meets the use standard, a formula and experimental data are recorded. According to the invention, different proportions of different raw materials are adjusted, and the viscosity reducing property of the prepared UV viscosity reducing adhesive tape is detected, so that the proportions of the raw materials in a formula are adjusted according to a detection result, and a proper formula is selected according to different use environments and use requirements, so that the stability of the UV viscosity reducing adhesive tape is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, and in particular to a UV anti-viscosity tape used in a PCB substrate cutting process and a preparation method thereof. Background Art

[0002] The existing PCB board cutting application is to stick the PVB board with UV viscosity-reducing glue and fix the UV viscosity-reducing tape with an iron ring, use a cutting machine to cut off the extra UV film on the edge, and then use a cutting machine to cut according to the specified size. There is a water gun cleaning during the cutting process, so there are certain requirements for the adhesion and water resistance of the tape in the cutting process, and after the glue is dissolved, it is also required that there is no residual glue or other pollution that affects the film removal process. The technology of the tape selected for general PCB substrate cutting is basically mature, but the cutting path and internal step difference of some large-size PCB substrates are relatively high. If the tape has insufficient filling, water resistance and adhesion to the step difference of the PCB substrate, it is easy to seep water and fly chips during cutting, and the current tape is prone to residual glue pollution after the PCB board with obvious step difference is reduced.

[0003] Chinese patent publication number: CN117165201A discloses a UV anti-viscosity tape and its application, comprising: a first substrate layer, a pressure-sensitive adhesive layer, a second substrate layer, a UV anti-viscosity adhesive layer and a release film layer stacked in sequence, wherein the UV anti-viscosity adhesive layer comprises the following components: 40-80 parts by weight of acrylate copolymer, 5-30 parts by weight of photocurable resin, 0.05-3 parts by weight of photoinitiator, 0.05-5 parts by weight of first curing agent, 0.5-10 parts by weight of first tackifying resin, and 20-80 parts by weight of first solvent. It can be seen that the UV anti-viscosity tape and its application have the following problems: it cannot be adjusted within the range of tissue components according to actual needs, so that the performance of the UV anti-viscosity tape during use in different environments cannot be guaranteed, and thus the stability of the UV anti-viscosity tape cannot be guaranteed. Summary of the invention

[0004] To this end, the present invention provides a UV anti-viscosity tape for a PCB substrate cutting process and a preparation method thereof, so as to overcome the problem that the stability of the UV anti-viscosity tape cannot be guaranteed in the prior art.

[0005] To achieve the above object, the present invention provides a method for preparing a UV anti-viscosity tape for a PCB substrate cutting process, comprising: Step S1, mixing a main resin, UV monomer and modified monomer, a photoinitiator, a curing agent, and a solvent in a preset ratio to prepare an adhesive, uniformly coating the prepared adhesive on a substrate to form a primary tape, and using an ultraviolet curing device to irradiate the primary tape with ultraviolet light to form a cured tape; Step S2, heat-treating the cured tape to output a UV-tested viscosity-reducing tape; Step S3, attaching the UV anti-viscosity tape to be tested to the corresponding test area on the surface of the PCB board, and using a peeling tester to peel the UV anti-viscosity tape to be tested from the surface of the PCB board to obtain the peeling strength of the UV anti-viscosity tape; Step S4, judging whether the viscosity reduction property of the UV viscosity reduction tape meets the use standard according to the peel strength of the UV viscosity reduction tape; if it is judged that the use standard is met, judging whether the formula of the UV viscosity reduction tape meets the use requirement according to the area of ​​the residual adhesive; if it is judged that the use standard is not met, determining the reason why the use standard is not met according to the ten-point elevation Rz of the tape surface or determining the reason why the viscosity reduction property does not meet the use standard according to the dust concentration on the surface of the PCB board; Step S5, executing a corresponding adjustment method according to the determination result of the reason for not meeting the use standard, the adjustment method includes: changing the formula, adjusting the attachment time of the UV anti-adhesive tape to be tested, and adjusting the peeling speed of the peeling tester.

[0006] Further, in S4, it is determined whether the tack-reducing property of the UV tack-reducing tape meets the use standard according to the peel strength of the UV tack-reducing tape to be tested. If the peel strength is less than the first-level strength, it is preliminarily determined that the tack-reducing property of the UV tack-reducing tape meets the use standard. If the peel strength is greater than or equal to the primary strength and less than or equal to the secondary strength, it is preliminarily determined that the tackiness of the UV tack-reducing tape does not meet the use standard and further determined whether it meets the use standard based on the roughness of the tape surface; If the peel strength is greater than the secondary strength, it is determined that the viscosity reduction property of the UV viscosity reducing tape does not meet the use standard, and the reason why the viscosity reduction property does not meet the use standard is determined based on the dust condition on the surface of the PCB board.

[0007] Further, when it is preliminarily determined that the viscosity reduction property of the UV viscosity reducing tape meets the use standard, whether the formula of the UV viscosity reducing tape meets the use requirements is judged according to the residual adhesive area on the surface of the PCB substrate after the peeling test. If the residual adhesive area on the surface of the PCB substrate is larger than the standard residual area, it is judged that the formula of the UV viscosity reducing tape does not meet the use requirements, and a formula change notice is issued; If the residual adhesive area on the surface of the PCB substrate is less than or equal to the standard residual area, it is determined that the formula of the UV anti-adhesive tape meets the use requirements, and the current formula is stored.

[0008] Further, when it is preliminarily determined that the viscosity reduction property of the UV viscosity reduction tape does not meet the use standard, whether the viscosity reduction property of the UV viscosity reduction tape meets the use standard is further determined according to the value of the ten-point elevation Rz of the UV viscosity reduction tape. If Rz is less than the first-level preset Rz, it is determined that the viscosity reduction property of the UV viscosity reduction tape does not meet the use standard. The reason why the viscosity reduction property does not meet the use standard is determined according to the surface dust concentration of the portion of the PCB substrate that has not been subjected to the 180° peel test; If the Rz is greater than or equal to the first-level preset Rz and less than or equal to the second-level preset Rz, it is determined that the tackiness of the UV anti-tack tape meets the use standard, and the preliminary determination result is that the reason for not meeting the use standard is that the attachment time is longer than the attachment time adapted to the current formula, and when the peel tester performs a 180° peel test according to Rz, the attachment time of the UV anti-tack tape and the PCB substrate is adjusted to a corresponding value; If the Rz is greater than the secondary preset Rz, it is determined that the viscosity reduction property of the UV viscosity reducing tape meets the use standard, and the preliminary judgment result is that the reason for not meeting the use standard is that the peeling speed is higher than the maximum peeling speed supported by the current formula, and the peeling speed during the 180° peeling test is adjusted to the corresponding value.

[0009] Furthermore, the calculation method of the ten-point elevation Rz is: after the peeling test is completed, the average height difference between the five highest peaks and the five lowest valleys on the surface of the UV anti-adhesive tape is selected.

[0010] Furthermore, if it is determined that the peeling speed of the peeling tester during the 180° peeling test is higher than the maximum peeling speed supported by the current formula, the adjustment range of the peeling speed during the 180° peeling test is determined by the difference between the Rz and the secondary preset Rz.

[0011] Furthermore, when it is determined that the viscosity reducing property of the UV viscosity reducing tape does not meet the use standard, the surface dust concentration of the PCB substrate surface that has not been subjected to the peeling test is determined by detecting through an imaging sensor, and the reason why the viscosity reducing property of the UV viscosity reducing tape does not meet the use standard is determined based on the surface dust concentration, including: the formula of the UV viscosity reducing tape does not meet the current use standard, and there is too much dust on the surface of the PCB substrate, resulting in insufficient contact between the UV viscosity reducing tape and the PCB substrate.

[0012] Further, when it is determined that the reason why the viscosity reduction property of the UV viscosity reducing tape does not meet the use standard is that there is too much dust on the surface of the PCB substrate, resulting in insufficient contact between the UV viscosity reducing tape and the PCB substrate, the PCB substrate is dusted and the current formula of the UV viscosity reducing tape is re-determined whether it meets the use standard based on the re-measured peel strength. If the re-determination result is a preliminary determination that the viscosity reduction property meets the use standard or does not meet the use standard, it is determined that the current formula of the UV viscosity reducing tape does not meet the use standard.

[0013] The present invention also provides a UV anti-viscosity tape for a PCB substrate cutting process, wherein the adhesive formula used in the UV anti-viscosity tape is: Main resin: accounting for 40%-65% by mass, the main resin is an acrylic copolymer composed of one or more of polyolefinic acid, polyacrylate, and polyurethane acrylate; UV monomers and modified monomers: polyurethane acrylate, urethane, accounting for 10%-30% by mass; Photoinitiator: 184 and TPO, accounting for 0.1%-3% by mass; Curing agent: isocyanate, accounting for 0.5%-2% by mass; Solvent: Toluene and ethyl acetate are added to the glue in a ratio of 1:2.

[0014] Furthermore, the structure of the UV adhesive tape includes: a substrate layer, a pressure-sensitive adhesive layer, and a release layer; The release layer is a PET single silicon release film layer, and the thickness can be selected from 38-50um; The substrate layer is a PO film or PVC material that meets halogen-free requirements.

[0015] Compared with the prior art, the beneficial effect of the present invention lies in that the formula of the UV anti-viscosity tape of the present invention can be adjusted within a certain range. By adjusting the different proportions of different raw materials and testing the anti-viscosity of the prepared UV anti-viscosity tape, the proportion of each raw material in the formula is adjusted according to the test results, so as to select a suitable formula according to different use environments and use requirements, thereby ensuring the stability of the UV anti-viscosity tape.

[0016] Furthermore, the quality of the UV anti-viscosity tape involves multiple parameters. Starting from the anti-viscosity, the present invention compares the measured peel strength with the peel strength required by the use standard, so as to determine whether the current formula meets the use requirements. When it is determined that the use standard is not met, the reason for not meeting the use standard is promptly determined, so that timely processing can be carried out, thereby further ensuring the stability of the UV anti-viscosity tape.

[0017] Furthermore, in actual applications, there may be a situation where the peeling strength is low but a large amount of residual glue will appear on the surface of the PCB substrate after peeling. Therefore, it is impossible to judge whether the current formula meets the use standard simply by the peeling strength. The present invention detects the area of ​​the residual glue on the surface of the PCB substrate to judge the situation of the residual glue, thereby making a more accurate judgment on the formula, thereby further ensuring the stability of the UV anti-viscosity tape.

[0018] Furthermore, the present invention detects the roughness of the tape surface after peeling by means of ten-point elevation Rz, thereby determining the adhesion condition between the UV anti-viscosity tape and the PCB substrate during the detection process, thereby taking external factors affecting the anti-viscosity into consideration for determination, thereby improving the accuracy of the determination result and further ensuring the stability of the UV anti-viscosity tape.

[0019] Furthermore, when conducting a peeling experiment, the peeling speed, the amount of dust, the attachment time, and the formula will all affect the anti-viscosity. The present invention calculates the first difference and the standard deviation and compares them with the use standard, thereby selecting a suitable adjustment coefficient according to the actual situation to adjust the corresponding parameters to the corresponding values, thereby further ensuring the stability of the UV anti-viscosity tape. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a flow chart of a method for preparing a UV anti-viscosity tape for a PCB substrate cutting process according to an embodiment of the present invention; Figure 2 This is a determination flow chart of a method for preparing a UV adhesive tape for a PCB substrate cutting process according to an embodiment of the present invention; Figure 3 A flow chart of determining how to adjust the attachment time in the method for preparing a UV adhesive tape for a PCB substrate cutting process according to an embodiment of the present invention; Figure 4 The present invention is a flowchart for determining a method for adjusting the peeling speed of a method for preparing a UV anti-viscosity tape for a PCB substrate cutting process according to an embodiment of the present invention. DETAILED DESCRIPTION

[0021] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0023] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be understood as a limitation on the present invention.

[0024] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0025] See also Figure 1 As shown, it is a flow chart of the method for preparing the UV anti-viscosity tape for the PCB substrate cutting process according to the present invention, comprising: Step S1, mixing a main resin, UV monomer and modified monomer, a photoinitiator, a curing agent, and a solvent in a preset ratio to prepare an adhesive, uniformly coating the prepared adhesive on a substrate to form a primary tape, and using an ultraviolet curing device to irradiate the primary tape with ultraviolet light to form a cured tape; Step S2, heat-treating the cured tape to output a UV-tested viscosity-reducing tape; Step S3, attaching the UV anti-viscosity tape to be tested to the corresponding test area on the surface of the PCB board, and using a peeling tester to peel the UV anti-viscosity tape to be tested from the surface of the PCB board to obtain the peeling strength of the UV anti-viscosity tape; Step S4, judging whether the viscosity reduction property of the UV viscosity reduction tape meets the use standard according to the peel strength of the UV viscosity reduction tape; if it is judged that the use standard is met, judging whether the formula of the UV viscosity reduction tape meets the use requirement according to the area of ​​the residual adhesive; if it is judged that the use standard is not met, determining the reason why the use standard is not met according to the ten-point elevation Rz of the tape surface or determining the reason why the viscosity reduction property does not meet the use standard according to the dust concentration on the surface of the PCB board; Step S5, executing a corresponding adjustment method according to the determination result of the reason for not meeting the use standard, the adjustment method includes: changing the formula, adjusting the attachment time of the UV anti-adhesive tape to be tested, and adjusting the peeling speed of the peeling tester.

[0026] Specifically, the test area is the area where the adhesive tape is subjected to a 180° peel test on the surface of the PCB substrate; Primary tape is the tape that has just been coated with adhesive but has not been cured; The cured adhesive tape is an adhesive tape that has been cured; The UV anti-viscosity tape to be tested is a UV anti-viscosity tape that has been prepared and is ready to be tested.

[0027] See also Figure 2As shown, it is a determination flow chart of the method for preparing a UV anti-viscosity tape for a PCB substrate cutting process according to an embodiment of the present invention. In S3, whether the anti-viscosity of the UV anti-viscosity tape meets the use standard is determined according to the peel strength of the UV anti-viscosity tape during a 180° peel test. If the peel strength is less than the first-level strength, it is preliminarily determined that the anti-viscosity of the UV anti-viscosity tape meets the use standard. If the peel strength is greater than or equal to the primary strength and less than or equal to the secondary strength, it is preliminarily determined that the tackiness of the UV tack-reducing tape does not meet the use standard, and the reason for not meeting the use standard is determined based on the roughness of the tape surface; If the peel strength is greater than the secondary strength, it is determined that the tackiness of the UV tack-reducing tape does not meet the use standard, and the reason why the measured tackiness does not meet the use standard is determined based on the dust condition on the surface of the PCB board; The primary strength and the secondary strength are determined according to the use standard. The embodiment of the present invention aims to obtain a peel strength below 4 N / cm, wherein the most preferred peel strength is below 3.2 N / cm. Therefore, the primary strength of the present invention is 3.2 N / cm, and the secondary preset strength is 4.0 N / cm.

[0028] Specifically, when it is preliminarily determined that the viscosity reduction property of the UV viscosity reducing tape meets the use standard, whether the formula of the UV viscosity reducing tape meets the use requirements is judged according to the residual adhesive area on the surface of the PCB substrate after the peeling test. If the residual adhesive area on the surface of the PCB substrate is larger than the standard residual area, it is judged that the formula of the UV viscosity reducing tape does not meet the use requirements, and a formula change notice is issued; If the residual adhesive area on the surface of the PCB substrate is less than or equal to the standard residual area, it is determined that the formula of the UV anti-adhesive tape meets the use requirements, and the current formula is stored.

[0029] The standard residual area is determined according to the use requirements. In the embodiment of the present invention, the use requirements require that the residual glue area is 1mm 2 Meters and below, the standard residual area value of the present invention is 1mm 2 .

[0030] Specifically, the residual adhesive area on the surface of the PCB substrate refers to the distribution area of ​​the residual adhesive on the surface of the PCB substrate after the peeling test.

[0031] Specifically, the residual adhesive area on the surface of the PCB substrate is obtained by an imaging sensor arranged in the peeling tester. The imaging sensor is a high-resolution camera that can capture images of the surface of an object and use machine vision technology to analyze dust particles and residual adhesive on the surface of the PCB substrate.

[0032] Specifically, when it is preliminarily determined that the viscosity reduction property of the UV viscosity reduction tape does not meet the use standard, the surface of the UV viscosity reduction tape after the 180° peel test is detected, and whether the viscosity reduction property of the UV viscosity reduction tape meets the use standard and the reason for the preliminarily determined viscosity reduction property not meeting the use standard are analyzed according to the value of the ten-point elevation Rz of the UV viscosity reduction tape. If Rz is less than the primary preset Rz, the viscosity reduction property of the UV viscosity reduction tape does not meet the use standard, and the reason for the viscosity reduction property not meeting the use standard is determined according to the surface dust concentration of the portion of the PCB substrate that is not subjected to the 180° peel test; the preferred embodiment of the primary preset Rz is 250 μm; If the Rz is greater than or equal to the primary preset Rz and less than or equal to the secondary preset Rz, the tackiness of the UV anti-tack tape meets the use standard, and it is preliminarily determined that the reason for not meeting the use standard is that the attachment time of the UV anti-tack tape to the surface of the PCB board is longer than the attachment time adapted by the current formula; the preferred embodiment of the secondary preset Rz is 400 μm; If the Rz is greater than the secondary preset Rz, the tackiness of the UV tack-reducing tape meets the use standard, and it is preliminarily determined that the reason for not meeting the use standard is that the peeling speed during the 180° peeling test is higher than the maximum peeling speed supported by the current formula, and the adhesive cannot be completely transferred to the adherend; The calculation method of the ten-point elevation Rz is: after the peeling test, the average height difference between the 5 highest peaks and the 5 lowest valleys on the surface of the UV anti-viscosity tape is in micrometers (μm); through multiple tests, it is determined that the range of Rz on the surface of the qualified UV anti-viscosity tape is (250μm, 420μm), therefore, the replaceable mode of the first-level preset Rz and the second-level preset Rz is (250μm, 420μm), as long as the size relationship between the first-level preset Rz and the second-level preset Rz and the requirements of the current actual situation are met.

[0033] Specifically, elevation represents the degree of roughness. The higher the dust concentration, the higher the highest peak. Therefore, there is a relationship between dust concentration and elevation. High dust concentration will cause dust accumulation and thus increase the elevation, and increased dust concentration will lead to changes in elevation.

[0034] Specifically, the logical process of the present invention is to first determine whether the viscosity reduction property of the viscosity reduction tape meets the use standard based on the peel strength. There are three corresponding situations. The first is to preliminarily determine that the viscosity reduction property of the UV viscosity reduction tape meets the use standard; the second is to preliminarily determine that the viscosity reduction property of the UV viscosity reduction tape does not meet the use standard; the third is to determine that the viscosity reduction property of the UV viscosity reduction tape does not meet the use standard.

[0035] Specifically, when the ten-point elevation is at the first-level preset elevation and less than or equal to the second-level preset elevation, it is preliminarily determined that the reason why the viscosity reduction property of the UV viscosity reducing tape does not meet the use standard corresponds to the attachment time of the UV viscosity reducing tape to the surface of the PCB board being longer than the attachment time adapted by the current formula. When the ten-point elevation is greater than the second-level preset elevation, this interval corresponds to the reason why it is preliminarily determined that the viscosity reduction property of the UV viscosity reducing tape does not meet the use standard is that the peeling speed during the 180° peeling test is higher than the maximum peeling speed supported by the current formula, and the adhesive cannot be completely transferred to the adherend. In other words, different intervals correspond to different reasons. In other words, the reason of excessive peeling speed is greater than the degree to which the viscosity reduction performance of the viscosity reducing tape does not meet the requirements due to excessive attachment time.

[0036] See also Figure 3 As shown, it is a determination flow chart for adjusting the attachment time of the method for preparing a UV anti-adhesive tape for a PCB substrate cutting process according to an embodiment of the present invention, the difference between the Rz and the first-level preset Rz is recorded as the first difference and the attachment time is adjusted according to the first difference, if the first difference is greater than the first-level preset first difference, the attachment time is adjusted to a corresponding value using a first adjustment coefficient; a preferred embodiment of the first adjustment coefficient is 0.85, and a preferred embodiment of the first difference is 95 μm; If the first difference is less than or equal to the first level preset first difference and greater than or equal to the second level preset first difference, the attachment time is adjusted to a corresponding value using a second adjustment coefficient; a preferred embodiment of the second adjustment coefficient is 0.90, and a preferred embodiment of the second difference is 65 μm; If the first difference is less than the second-level preset first difference, the attachment duration is adjusted to a corresponding value using a third adjustment coefficient; a preferred embodiment of the third adjustment coefficient is 0.95; The UV anti-adhesive tape used in the PCB substrate cutting process generally has a general attachment time of about 24-72 hours. In the embodiment of the present invention, the initial attachment time is selected as 36 hours, and the adjustment coefficient of the attachment time can be replaced by (0.90, 0.99). When selecting, it is necessary to pay attention to the relationship of the first adjustment coefficient < the second adjustment coefficient < the third adjustment coefficient.

[0037] See also Figure 4As shown, it is a determination flow chart of the peeling speed adjustment method of the UV anti-viscosity tape preparation method for PCB substrate cutting process described in an embodiment of the present invention, the difference between the Rz and the secondary preset Rz is recorded as the standard deviation value and the peeling speed of the peeling tester during the 180° peeling test is adjusted according to the standard deviation value. If the standard deviation value is greater than the primary standard deviation value, the first speed adjustment coefficient is used to adjust the peeling speed to the corresponding value; the preferred embodiment of the first speed adjustment coefficient is 0.94, and the preferred embodiment of the primary standard deviation value is 125μm; If the standard deviation value is less than or equal to the standard deviation value used in the first stage and greater than or equal to the standard deviation value used in the second stage, the stripping speed is adjusted to the corresponding value using the second speed adjustment coefficient; the preferred embodiment of the second speed adjustment coefficient is 0.96, and the preferred embodiment of the standard deviation value used in the second stage is 65 μm; If the standard deviation value is smaller than the secondary standard deviation value, the stripping speed is adjusted to a corresponding value using a third speed adjustment coefficient; a preferred embodiment of the third speed adjustment coefficient is 0.98.

[0038] The speed adjustment coefficient can be replaced by (0.92, 0.99). When selecting, please note that the first speed adjustment coefficient < the second speed adjustment coefficient < the third speed adjustment coefficient.

[0039] Specifically, the reason for determining that the viscosity reduction property of the UV viscosity reducing tape does not meet the use standard is determined by visually detecting the surface dust concentration of the PCB substrate surface on which the peeling test is not performed. If the surface dust concentration is less than or equal to the preset surface dust concentration, it is determined that the reason for determining that the viscosity reduction property does not meet the use standard is that the formula of the UV viscosity reducing tape does not meet the current use standard. If the surface dust concentration is greater than the preset surface dust concentration, it is determined that the reason why the viscosity reduction property does not meet the use standard is that there is too much dust on the surface of the PCB substrate, resulting in insufficient contact between the UV viscosity reduction tape and the PCB substrate; IPC-A-610 (Acceptance Standard for Electronic Assembly Products) has the following requirements for dust concentration on PCB surface: Class 1 (general electronic products): ≤1.5 μg / cm²; Class 2 (high reliability electronic products): ≤1.0 μg / cm²; Class 3 (high-performance electronic products): ≤0.5 μg / cm²; Experiments have shown that when the surface dust concentration is 0.5 μg / cm², it will have a more obvious effect on the viscosity reduction. Therefore, the preset surface dust concentration in the present invention is preferably 0.5 μg / cm².

[0040] Specifically, when it is determined that the reason why the viscosity reduction property does not meet the use standard is that there is too much dust on the surface of the PCB substrate, resulting in insufficient contact between the UV viscosity reduction tape and the PCB substrate, the PCB substrate is dusted and the current formula of the UV viscosity reduction tape is re-determined whether it meets the use standard based on the re-measured peel strength. If the result of the re-determination is a preliminary determination that the viscosity reduction property meets the use standard or does not meet the use standard, it is determined that the current formula does not meet the use standard and a formula adjustment notice is issued.

[0041] Specifically, the adhesive formula used in the UV anti-viscosity tape is: The main resin accounts for 40% to 65% by weight. The main resin is an acrylic copolymer composed of one or more of polyolefinic acid, polyacrylate, and polyurethane acrylate; UV monomers and modified monomers: polyurethane acrylate, urethane, accounting for 10%-30% by mass; Among them, the polyurethane acrylate and carbamate in the UV monomer and the modified monomer are preferably difunctional monomers; Photoinitiator: 184 and TPO, accounting for 0.1%-3% by mass; Curing agent: isocyanate, accounting for 0.5%-2% by mass; Solvent: Toluene and ethyl acetate, mixed in a ratio of 1:2.

[0042] Specifically, the tape structure is as follows: the substrate layer is provided with a pressure-sensitive adhesive layer and a release layer; The substrate layer is PO / PVC. Considering the halogen-free requirement, PO material is preferred. The thickness can be 60-90um, the modulus can be 50-120MPa, and 75um, 80MPa PO film is preferred.

[0043] Specifically, the release layer is a PET single silicon release film layer, and the thickness can be selected to be 38-50um.

[0044] The present invention also provides some formulas and corresponding properties obtained through experiments.

[0045]

[0046]

[0047] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a UV adhesive tape for a PCB substrate cutting process, characterized in that: The following steps are involved: Step S1, mixing a main resin, UV monomer and modified monomer, a photoinitiator, a curing agent, and a solvent in a preset ratio to prepare an adhesive, uniformly coating the prepared adhesive on a substrate to form a primary tape, and using an ultraviolet curing device to irradiate the primary tape with ultraviolet light to form a cured tape; Step S2, heat-treating the cured tape to output a UV-tested viscosity-reducing tape; Step S3, attaching the UV anti-viscosity tape to be tested to the corresponding test area on the surface of the PCB board, and using a peeling tester to peel the UV anti-viscosity tape to be tested from the surface of the PCB board to obtain the peeling strength of the UV anti-viscosity tape; Step S4, judging whether the viscosity reduction property of the UV viscosity reduction tape meets the use standard according to the peel strength of the UV viscosity reduction tape; if it is judged that the use standard is met, judging whether the formula of the UV viscosity reduction tape meets the use requirement according to the area of ​​the residual adhesive; if it is judged that the use standard is not met, determining the reason why the use standard is not met according to the ten-point elevation Rz of the tape surface or determining the reason why the viscosity reduction property does not meet the use standard according to the dust concentration on the surface of the PCB board; Step S5, executing a corresponding adjustment method according to the determination result of the reason for not meeting the use standard, the adjustment method includes: changing the formula, adjusting the attachment time of the UV anti-adhesive tape to be tested, and adjusting the peeling speed of the peeling tester.

2. The method for preparing a UV adhesive tape for a PCB substrate cutting process according to claim 1, characterized in that: In S4, whether the tack-reducing property of the UV tack-reducing tape meets the use standard is determined according to the peel strength of the UV tack-reducing tape to be tested. If the peel strength is less than the first-level strength, it is preliminarily determined that the tack-reducing property of the UV tack-reducing tape meets the use standard. If the peel strength is greater than or equal to the primary strength and less than or equal to the secondary strength, it is preliminarily determined that the tackiness of the UV tack-reducing tape does not meet the use standard and further determined whether it meets the use standard based on the roughness of the tape surface; If the peel strength is greater than the secondary strength, it is determined that the viscosity reduction property of the UV viscosity reducing tape does not meet the use standard, and the reason why the viscosity reduction property does not meet the use standard is determined based on the dust condition on the surface of the PCB board.

3. The method for preparing a UV anti-viscosity tape for a PCB substrate cutting process according to claim 2, characterized in that: When it is preliminarily determined that the viscosity reduction property of the UV viscosity reduction tape meets the use standard, whether the formula of the UV viscosity reduction tape meets the use requirements is judged according to the residual adhesive area on the surface of the PCB substrate after the peeling test. If the residual adhesive area on the surface of the PCB substrate is larger than the standard residual area, it is judged that the formula of the UV viscosity reduction tape does not meet the use requirements, and a formula change notice is issued; If the residual adhesive area on the surface of the PCB substrate is less than or equal to the standard residual area, it is determined that the formula of the UV anti-adhesive tape meets the use requirements, and the current formula is stored.

4. The method for preparing a UV adhesive tape for a PCB substrate cutting process according to claim 2, characterized in that: When it is preliminarily determined that the viscosity reduction property of the UV viscosity reduction tape does not meet the use standard, whether the viscosity reduction property of the UV viscosity reduction tape meets the use standard is further determined based on the value of the ten-point elevation Rz of the UV viscosity reduction tape. If Rz is less than the first-level preset Rz, it is determined that the viscosity reduction property of the UV viscosity reduction tape does not meet the use standard. The reason why the viscosity reduction property does not meet the use standard is determined based on the surface dust concentration of the portion of the PCB substrate that has not been subjected to the 180° peel test; If the Rz is greater than or equal to the first-level preset Rz and less than or equal to the second-level preset Rz, it is determined that the tackiness of the UV anti-tack tape meets the use standard, and the preliminary determination result is that the reason for not meeting the use standard is that the attachment time is longer than the attachment time adapted to the current formula, and when the peel tester performs a 180° peel test according to Rz, the attachment time of the UV anti-tack tape and the PCB substrate is adjusted to a corresponding value; If the Rz is greater than the secondary preset Rz, it is determined that the viscosity reduction property of the UV viscosity reducing tape meets the use standard, and the preliminary judgment result is that the reason for not meeting the use standard is that the peeling speed is higher than the maximum peeling speed supported by the current formula, and the peeling speed during the 180° peeling test is adjusted to the corresponding value.

5. The method for preparing a UV adhesive tape for a PCB substrate cutting process according to claim 4, characterized in that: The calculation method of the ten-point elevation Rz is as follows: after the peeling test is completed, the average height difference between the five highest peaks and the five lowest valleys on the surface of the UV anti-adhesive tape is selected.

6. The method for preparing a UV adhesive tape for a PCB substrate cutting process according to claim 4, characterized in that: If it is determined that the peeling speed of the peeling tester during the 180° peeling test is higher than the maximum peeling speed supported by the current formula, the adjustment range of the peeling speed during the 180° peeling test is determined by the difference between the Rz and the secondary preset Rz.

7. The method for preparing a UV adhesive tape for a PCB substrate cutting process according to claim 2, characterized in that: When it is determined that the viscosity reducing property of the UV viscosity reducing tape does not meet the use standard, the surface dust concentration of the PCB substrate surface that has not been subjected to the peeling test is determined by detecting with an imaging sensor, and the reason why the viscosity reducing property of the UV viscosity reducing tape does not meet the use standard is determined based on the surface dust concentration, including: the formula of the UV viscosity reducing tape does not meet the current use standard, and there is too much dust on the surface of the PCB substrate, resulting in insufficient contact between the UV viscosity reducing tape and the PCB substrate.

8. The method for preparing a UV adhesive tape for a PCB substrate cutting process according to claim 7, characterized in that: When it is determined that the reason why the viscosity reduction property of the UV viscosity reducing tape does not meet the use standard is that there is too much dust on the surface of the PCB substrate, resulting in insufficient contact between the UV viscosity reducing tape and the PCB substrate, the PCB substrate is dusted and the current formula of the UV viscosity reducing tape is re-determined whether it meets the use standard based on the re-measured peel strength. If the re-determination result is a preliminary determination that the viscosity reduction property meets the use standard or does not meet the use standard, it is determined that the current formula of the UV viscosity reducing tape does not meet the use standard.

9. A UV anti-viscosity tape prepared by the method for preparing a UV anti-viscosity tape for a PCB substrate cutting process according to any one of claims 1 to 8, characterized in that: The adhesive formula used for the UV adhesive tape is: Main resin: accounting for 40%-65% by mass, the main resin is an acrylic copolymer composed of one or more of polyolefinic acid, polyacrylate, and polyurethane acrylate; UV monomers and modified monomers: polyurethane acrylate, urethane, accounting for 10%-30% by mass; Photoinitiator: 184 and TPO, accounting for 0.1%-3% by mass; Curing agent: isocyanate, accounting for 0.5%-2% by mass; Solvent: Toluene and ethyl acetate are added to the glue in a ratio of 1:

2.

10. The UV adhesive tape for PCB substrate cutting process according to claim 9, characterized in that: The structure of the UV adhesive tape includes: a substrate layer, a pressure-sensitive adhesive layer, and a release layer; The release layer is a PET single silicon release film layer, and the thickness can be selected from 38-50um; The substrate layer is a PO film or PVC material that meets halogen-free requirements.

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