JP2006322923A - Evaluation method and manufacturing method for rubber, and manufacturing method for joint seal for ink jet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an evaluation method for rubber capable of evaluating a degree of crosslinking in a short time, without special treatment, even in a rubber product after crosslinking, a manufacturing method for the rubber capable of obtaining the desired degree of crosslinking, using the evaluation method, and a manufacturing method for a joint seal for an ink jet printer using the evaluation method. <P>SOLUTION: In this evaluation method, an energy shift amount of a component element peak (Cl2p3/2 peak or the like of chlorinated butyl rubber) of the rubber is measured by photoelectron spectroscopic measurement, and the degree of crosslinking of the rubber is evaluated based on the energy shift amount. In this manufacturing method for the rubber, the component element peak of the rubber is measured in a process assembled with a photoelectron spectrometer in line, a result therein is fed back and a hot-molding condition is thereby regulated to bring the desired degree of crosslinking. This manufacturing method for the joint seal for the ink jet printer uses the evaluation method. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for evaluating the degree of crosslinking of rubber, a method for producing rubber that obtains a desired degree of crosslinking using the evaluation method, and a method for producing a joint seal for an ink jet printer using the evaluation method.

  The degree of crosslinking of rubber is an important factor that affects the physical properties of rubber, and evaluation of the degree of crosslinking is indispensable for product design and product inspection. In general, the degree of rubber cross-linking is often measured by a swelling test. However, the evaluation of the degree of cross-linking by the swelling test is a technique in which a rubber sample is immersed in a solvent and the swelling ratio is measured, and therefore requires several days. In addition, when the amount of rubber to be evaluated is small, measurement errors increase and it is difficult to obtain an accurate degree of crosslinking.

  As another method for measuring the degree of rubber cross-linking, there is a method of measuring the torque of rubber with a curast meter and evaluating the degree of cross-linking from the value of this torque. In this method, unvulcanized rubber is used as a sample, and a vulcanization curve is created for this unvulcanized rubber sample with the horizontal axis representing time and the vertical axis representing torque, and the degree of rubber crosslinking is evaluated from this vulcanization curve. Is the method. However, the sample piece used for the curastometer measurement needs to have a certain size or more and a specific shape, which is different from the actual product form. For this reason, it is difficult to find the exact crosslinking conditions of the rubber in the product form from the measurement with a curast meter. In addition, since it cannot be applied to a crosslinked rubber, the degree of crosslinking of the actually produced rubber product itself cannot be evaluated.

As another method for measuring the degree of crosslinking of rubber, there is a method for evaluating the degree of crosslinking of rubber based on measurement of relaxation time by solid state NMR (nuclear magnetic resonance) (see Patent Document 1 and Patent Document 2). However, in the measurement method by solid-state NMR, since the measurement is performed at a high speed of several tens of thousands rpm, it is necessary to uniformly pack the sample in the spinner in order to avoid the eccentricity of the spinner (rotary tube) in which the sample is inserted. Therefore, it is difficult to use the product form itself for the measurement, and a pretreatment for the measurement such as cutting a rubber sample into a spinner inner diameter shape or processing into a powder form is required. In addition, the obtained information is average information from the entire sample, and variation when the degree of cross-linking is partially different cannot be evaluated.
JP-A-8-122284 JP 2002-71595 A

  The present invention has been made in view of the above points, and a rubber evaluation method capable of evaluating the degree of cross-linking in a short time without special treatment even in a rubber product after cross-linking, and a desired cross-linking using the evaluation method It aims at providing the manufacturing method of the rubber | gum which obtains a degree. Moreover, it aims at providing the manufacturing method of the joint seal for inkjet printers using the evaluation method.

  As a result of intensive investigations on means for evaluating the degree of crosslinking of the crosslinked rubber, the present inventor has found a very useful parameter for evaluating the degree of crosslinking of the rubber. Specifically, it has been found for the first time that the energy value of a specific peak measured using photoelectron spectroscopy shifts almost linearly according to the degree of crosslinking of rubber. If this is used to indirectly evaluate the degree of crosslinking of the rubber, the degree of crosslinking of the product itself can be evaluated in a short time without any special treatment, and good quality control becomes possible.

  That is, the present invention is a rubber evaluation method characterized by measuring the amount of energy shift of the component element peak of rubber by photoelectron spectroscopy and evaluating the degree of crosslinking of the rubber from the amount of energy shift.

  Furthermore, the present invention is a rubber evaluation method characterized by measuring the amount of energy shift of the component element peak of chlorinated butyl rubber by photoelectron spectroscopy and evaluating the degree of crosslinking of the chlorinated butyl rubber from the amount of energy shift. .

  Furthermore, the present invention includes a step of molding rubber by heat crosslinking, a step of measuring an energy shift amount of a component element peak of the molded rubber, a step of calculating the degree of crosslinking of the rubber from the energy shift amount, and the calculation result And a step of feeding back to the step of molding the rubber.

  Furthermore, the present invention relates to a method for manufacturing a joint seal made of chlorinated butyl rubber for an ink jet printer having a step of heat-crosslinking during molding, in the chlorinated butyl rubber of the joint seal after molding in a step in which the photoelectron spectrometer is incorporated in-line. The energy shift amount of the Cl2p3 / 2 peak is measured, and this measurement value is fed back during the process, and the heating molding conditions are adjusted so that the energy shift value of the Cl2p3 / 2 peak is within the range of 0.6 eV ± 0.3 eV. It is a manufacturing method of the joint seal for inkjet printers characterized by adjusting.

  According to the present invention, it is possible to evaluate the degree of rubber cross-linking by using the product form rubber as it is for measurement without requiring any special treatment. Moreover, since the method is based on photoelectron spectroscopy, the sample area required for one measurement is small (several tens of microns to several millimeters), and the degree of cross-linking of a part of a desired product can be evaluated. It is also possible to evaluate the degree distribution and variation.

  In particular, applying the evaluation method of the present invention to a rubber production process, specifically, evaluating the degree of rubber cross-linking easily and quickly during the production process if a photoelectron spectrometer is incorporated in-line in the process line. Is possible. Thereby, a rubber having a constant degree of crosslinking can be easily and accurately produced.

  The present invention is particularly useful when applied to the manufacture of joint seals and the like made of chlorinated butyl rubber used in ink jet printers.

  In the present invention, the degree of crosslinking of the rubber is evaluated based on the energy shift amount of the component element peak of the rubber by photoelectron spectroscopy (hereinafter referred to as “XPS”) measurement. This XPS measurement is an analysis method in which a sample is irradiated with X-rays in an ultrahigh vacuum, and the energy of emitted photoelectrons is measured with an energy analyzer. As excitation X-rays, for example, those having relatively low energy such as Kα of Al or Mg can be used. Energy analyzers are devices that measure the kinetic energy of electrons using an electric field, and include concentric hemispherical (CHA), concentric cylindrical (CMA), and the like.

  The electrons that make up the atoms are bound to a certain strength from the nucleus, and the kinetic energy of the photoelectrons emitted when the X-rays are applied is a value obtained by subtracting the binding energy from the excitation light energy. . In principle, the binding energy is a value determined by the type of atom and the orbit of the electron, but when the atom constitutes a compound, the value changes compared to the free state, and this is a chemical shift. Call it.

  The present invention has been completed on the basis of the new knowledge that the energy shift amount of the component element peak of rubber by XPS measurement changes linearly, that is, almost linearly, with respect to the increase or decrease of the degree of crosslinking. is there.

  According to the knowledge of the present inventor, for example, the degree of crosslinking of chlorinated butyl rubber and the energy shift amount of Cl2p3 / 2 of chlorinated butyl rubber in XPS measurement have a linear function relationship. The reason why the value of Cl2p3 / 2 shifts depending on the degree of crosslinking of the chlorinated butyl rubber can be interpreted as follows. As shown in FIG. 1, in chlorinated butyl rubber, Cl atoms are chemically bonded (covalently bonded) to surrounding C atoms, but nearby C atoms that are not bonded are weak due to intermolecular interactions. Are connected. In addition, Cl atoms are slightly positive because they share electrons with C atoms, and therefore Cl electrons are strongly captured by this positive charge. Therefore, when XPS measurement is performed, it is considered that the Eb (binding energy) shifts to a higher level, and the shift of the Cl energy level increases as the number of adjacent molecules increases. In general, in a rubber structure, molecules form a network structure, so that the higher the degree of crosslinking, the more likely the chlorine atom is to be affected by many neighboring molecules (intermolecular interaction). Therefore, it is considered that the energy shift of Cl2p3 / 2 increases as the degree of crosslinking increases.

  The present invention has been made on the basis of the above knowledge, and the XPS measurement of the energy shift amount of Cl atoms is performed, and the degree of crosslinking of the rubber is evaluated based on the measurement result.

  Unlike the torque measurement (crosslinking degree measurement) by the NMR method or the curast meter, the evaluation of the crosslinking degree by XPS measurement has a great advantage that the crosslinked rubber product itself can be evaluated. In addition, since the measurement can be performed in a small region of several tens of μm to several mm, the distribution of the degree of crosslinking can be evaluated at each part of the molding.

  For example, when a joint seal is molded by the injection method using chlorinated butyl rubber, the Cl2p3 / 2 peak shifts to the higher energy side as the degree of crosslinking of the rubber increases as measured by XPS. Specifically, the relationship is as shown in FIG. Therefore, the degree of cross-linking can be evaluated by measuring the energy shift amount of the Cl2p3 / 2 peak, and the result can be fed back to the injection conditions to provide a joint seal with minimal cross-linking degree variation. .

  In addition, the joint seal for inkjet printers is applicable to the form shown, for example in FIG. In FIG. 7, the recording head unit includes a recording element unit H1002, an ink supply unit H1003, and a tank holder H2000. The ink supply unit H1003 is connected to the recording element unit H1002 via a joint seal member H2300. As a result, ink in an ink tank (not shown) can be supplied to the recording element unit H1002.

  The joint seal of the present invention is not limited to the above example. Specifically, the present invention can be applied to a rubber member for sealing the hole of the ink chamber of the ink cartridge. When the ink cartridge is jointed, the joint seal is pierced by the joint needle, but the portion around the joint needle in the pierced portion is closed by elastic contraction of rubber, and functions so that ink flows only inside the joint needle. Furthermore, the present invention can also be applied to a joint seal disposed around the ink supply port of a tank holder that can be attached with a detachable ink tank.

  FIG. 3 is a diagram showing a flow of a rubber manufacturing process (joint seal manufacturing process). Here, the above-described XPS apparatus is incorporated during the manufacturing process. As shown in this flow, for example, a) uncrosslinked chlorinated butyl rubber as a raw material is prepared, and b) an inorganic additive, a deterioration inhibitor, a crosslinking agent, and the like are added. Further, c) preheating is performed, d) injection molding or compression molding is performed, e) XPS measurement is performed, and f) a joint seal rubber product is obtained. Here, for example, the energy shift amount of Cl2p3 / 2 is obtained by XPS measurement for the rubber after the molding after the step d), and thereby the degree of crosslinking is evaluated. When the measured value of the energy shift amount deviates from the design value, the molding conditions or the synthesis conditions are adjusted until the degree of crosslinking reaches a desired value. Specifically, when measuring the energy shift amount of the Cl2p3 / 2 peak in the chlorinated butyl rubber, it is preferable to adjust the energy shift amount to be in the range of 0.6 eV ± 0.3 eV. This is because if it is out of the above range, the sealing property of the ink is impaired as described later. When the measured value matches the design value, the assembly of the joint seal into the product is started. This series of work steps can be performed as sampling inspections at regular intervals, for example.

  Hereinafter, the present invention will be specifically described by way of examples.

[Torque measurement with curast meter]
First, in order to clarify the relationship between the degree of cross-linking of the rubber to be evaluated, the heating time, and the heating temperature, torque measurement with a curast meter was performed as follows using an unvulcanized chlorinated butyl rubber composition ( The degree of crosslinking was measured).

  An inorganic additive such as a vulcanization accelerator and an organic deterioration inhibitor were added to chlorinated butyl rubber and kneaded to prepare an unvulcanized (uncrosslinked) chlorinated butyl rubber composition (A). Next, it was examined how the torque changes with time while maintaining a constant temperature. The result is shown in FIG. It was found that the crosslinking rate was slow at low temperatures, the crosslinking proceeded quickly at high temperatures, and the crosslinking was completed in a short time. In FIG. 5, the horizontal axis is changed to the bridging temperature and the vertical axis is changed to the torque based on the result of FIG. From this figure, it can be seen that the degree of crosslinking of the chlorinated butyl rubber can be controlled by changing the heating temperature.

  Next, using the same unvulcanized chlorinated butyl rubber composition (A) as described above, a low-bridge joint seal (D) and a high-bridge joint seal (E) were produced by a compression method. The torque (crosslinking degree) of the low bridge joint seal (D) is 0.15, and the torque (crosslinking degree) of the high bridge joint seal (E) is 0.45.

[Plot of XPS measurement value and evaluation of crosslinking degree]
Next, for each of the unvulcanized chlorinated butyl rubber composition (A), low-crosslinking joint seal (D), and high-crosslinking joint seal (E), the energy value of Cl2p3 / 2 of the chlorinated butyl rubber was measured by the XPS method. did.

The measurement conditions are as follows.
Measurement device: JPS-9200 (JEOL).
Measurement conditions: X-ray = MgKα, output = 200 W (10 kV × 20 mA).
・ Measurement diameter: 1mmφ.
Energy resolution: analyzer passing energy 10 eV (0.9 eV at Ag3d5 / 2 peak).
Measurement elements: F1s, O1s, Cl2p, Si2p.

  As a result of this XPS measurement, the energy value of Cl2p3 / 2 of the unvulcanized chlorinated butyl rubber (A) was 198.248 eV, and the energy value of Cl2p3 / 2 of the low-bridge joint seal (D) was 198.77 eV. Furthermore, the energy value of Cl2p3 / 2 of the viaduct joint seal (E) was 199.082 eV.

  That is, the energy shift amount of Cl2p3 / 2 of the low bridge joint seal (D) having a torque of 0.15 is 0.522, and the energy shift amount of Cl2p3 / 2 of the high bridge joint seal (E) having a torque of 0.45 is 0.834. It is.

  Based on these data, the horizontal axis represents the degree of cross-linking obtained from the torque measurement, and the vertical axis plotted the energy shift amount obtained from the XPS measurement to create a calibration curve as shown in FIG. . In the figure, data (D) and (E) are indicated by “●”. As shown in this figure, the degree of crosslinking and the amount of energy shift are in a linear function, and the relationship between both changes is represented by a straight line.

  Next, joint seal (B) and joint seal (C) were produced by the injection method using the same unvulcanized chlorinated butyl rubber composition (A) as described above. About each of these joint seals (B) and (C), the energy value of Cl2p3 / 2 of chlorinated butyl rubber was similarly measured by XPS method.

  As a result of XPS measurement, the energy value of Cl2p3 / 2 of the joint seal (B) was 198.864 eV, and the energy value of Cl2p3 / 2 of the joint seal (C) was 199.168 eV.

  That is, the energy shift amount of Cl2p3 / 2 of the joint seal (B) is 0.616, and the energy shift amount of Cl2p3 / 2 of the joint seal (C) is 0.920.

  When the degree of cross-linking corresponding to these values is obtained from the calibration curve in FIG. 2, the degree of cross-linking of the joint seal (B) is 0.32, and the degree of cross-linking of the joint seal (C) is 0.57. In the figure, the data of (B) and (C) is indicated by “□”.

  Moreover, the spectrum which is a result of the XPS measurement of the above (A)-(E) is shown in FIG. In the Cl2p spectrum, two peaks of 2p3 / 2 and 2p1 / 2 appear. Of these two, the peak position of 2p3 / 2 is gradually shifted to the high binding energy side as the degree of crosslinking increases. I understand that

  For the joint seals (B) and (C), the degree of crosslinking generally expected from the crosslinking molding conditions and the measurement data of the curast meter is both 0.32. However, even if the same molding conditions are used, if the molding date and time and the lot of rubber material are different, the same degree of crosslinking is not always reproduced. The reason why the degree of cross-linking of the molded chlorinated butyl rubber does not necessarily match the set value is due to differences in molding method, existence of temperature distribution, subtle deviation in temperature measurement, variation in rubber material components, etc. it is conceivable that.

  When the degree of crosslinking of the rubber increases, the inherent properties of the rubber are impaired by curing, and the stable function as a rubber product may not be achieved. From this point, in this embodiment, (B) is a non-defective product and (C) is a defective product as a joint seal for an ink jet printer.

  From these points, in order to maintain the desired degree of crosslinking of the molded rubber and perform sufficient quality control, the degree of crosslinking is measured for the actual molded rubber product, and the result is used as the molding condition. It is important to provide feedback. Therefore, it is very useful to evaluate the degree of cross-linking of an actual molded joint seal by XPS measurement as in this example. Specifically, in the manufacturing process, the degree of cross-linking of the product is sequentially evaluated by sampling inspection, and when a defective product with a high degree of cross-linking such as (C) occurs, the information is fed back, and the heating temperature and heating time Change the heating molding conditions. Thereby, it is possible to easily and satisfactorily manage the product simply by adjusting the energy shift value of the Cl2p3 / 2 peak to be preferably in the range of 0.6 eV ± 0.3 eV.

It is a schematic diagram which shows the state of the molecule | numerator in bridge | crosslinking chlorinated butyl rubber. It is a figure which shows the calibration curve created from the data of the rubber crosslinking degree of an Example, the energy shift amount, and the data. It is a figure which shows the flow of the manufacturing process of rubber | gum. It is a figure which shows the relationship between crosslinking time and a crosslinking degree. It is a figure which shows the relationship between a crosslinking temperature and a crosslinking degree. It is a figure which shows the spectrum acquired by the XPS measurement of the sample (A)-(E) of an Example. FIG. 2 is an exploded perspective view of a recording head portion of an ink jet recording head cartridge to which a joint rubber according to an embodiment is applied.

Explanation of symbols

H1003 Ink supply unit H1002 Recording element unit H2000 Tank holder H2300 Joint seal member

Claims (5)

  A rubber evaluation method, comprising: measuring an energy shift amount of a component element peak of rubber by photoelectron spectroscopy measurement; and evaluating a degree of crosslinking of the rubber from the energy shift amount.   A rubber evaluation method comprising measuring an energy shift amount of a component element peak of chlorinated butyl rubber by photoelectron spectroscopy, and evaluating a degree of crosslinking of the chlorinated butyl rubber from the energy shift amount.   3. The rubber evaluation method according to claim 2, wherein an energy shift amount of a Cl2p3 / 2 peak of the chlorinated butyl rubber is measured.   The step of molding rubber by heat crosslinking, the step of measuring the energy shift amount of the component element peak of the molded rubber, the step of calculating the degree of crosslinking of the rubber from the amount of energy shift, the molding result of the rubber And a step of feeding back to the step of performing a process for producing rubber.   In a method for manufacturing a joint seal made of chlorinated butyl rubber for an ink jet printer having a step of heat-crosslinking during molding, the Cl2p3 / 2 peak in the chlorinated butyl rubber of the joint seal after molding in a step in which the photoelectron spectrometer is incorporated in-line The amount of energy shift is measured, and this measurement value is fed back during the process, and the heat molding conditions are adjusted so that the energy shift value of the Cl2p3 / 2 peak is within the range of 0.6 eV ± 0.3 eV. A method for manufacturing a joint seal for an inkjet printer.

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