JP7292820B2 - Liquid crystal polymer powder, paste, resin multilayer substrate, and method for manufacturing resin multilayer substrate - Google Patents

Description

The present invention relates to a liquid crystal polymer powder, a paste, a resin multilayer substrate, and a method for manufacturing a resin multilayer substrate.

In International Publication WO2014/109139 (Patent Document 1), when manufacturing a resin multilayer substrate by laminating and thermocompression bonding a plurality of resin layers, a paint layer is formed in a partial region of the resin layer, It is described that powdery liquid crystal polymer dispersed in a liquid is used as a material for this paint layer.

International publication WO2014/109139

Even if a powdery liquid crystal polymer dispersed in a liquid is used as a paint, it is not always possible to obtain stable adhesion between the resin layers.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a liquid crystal polymer powder, a paste, a resin multilayer substrate, and a method for manufacturing a resin multilayer substrate that can stably obtain adhesion between resin layers.

To achieve the above object, the liquid crystal polymer powder according to the present invention contains a C═O peak in the C1s peak of the C1s narrow scan spectrum obtained by X-ray photoelectron spectroscopy.

ADVANTAGE OF THE INVENTION According to this invention, the adhesiveness of resin layers can be obtained stably.

1 is a schematic diagram of a liquid crystal polymer powder according to Embodiment 1 of the present invention; FIG. FIG. 2 is a diagram showing an example of a C1s narrow scan spectrum obtained from a liquid crystal polymer powder in Embodiment 1 of the present invention; FIG. 2 is a diagram showing a further resolved state of the C1s peak of the C1s narrow scan spectrum obtained from the liquid crystal polymer powder in Embodiment 1 based on the present invention. FIG. 2 is a schematic diagram of liquid crystal polymer powder obtained by freeze pulverizing and sieving a liquid crystal polymer film. FIG. 2 is a schematic diagram of a dispersion prepared by dispersing liquid crystal polymer powder. 1 is an exploded view of an ultraviolet irradiation device having a double-tube structure; FIG. It is explanatory drawing of the use condition of the ultraviolet irradiation device of a double tube structure. FIG. 4 is an explanatory diagram of how a sample and a dispersion medium are mixed in an experimental example. FIG. 4 is an explanatory diagram showing how a paste was obtained by sufficiently dispersing a sample in a dispersion medium in an experimental example. FIG. 10 is an explanatory diagram of how a coating film is formed on the surface of a liquid crystal polymer film in an experimental example. FIG. 10 is an explanatory view showing how a liquid crystal polymer film having a coating film formed thereon and another liquid crystal polymer film are superimposed in an experimental example. FIG. 3 is a perspective view of a laminate obtained by stacking two liquid crystal polymer films in an experimental example. In an experimental example, it is a perspective view of the state where the layered product was cut into strips. FIG. 10 is an explanatory diagram of how to obtain the T-peel strength using a strip-shaped laminate in an experimental example. It is a schematic diagram of the paste in Embodiment 2 based on this invention. 3 is a flow chart of a method for manufacturing a resin multilayer substrate according to Embodiment 3 of the present invention. FIG. 11 is a cross-sectional view showing a state in which a paint layer is formed on a resin sheet as part of a method for manufacturing a resin multilayer substrate according to Embodiment 3 of the present invention; FIG. 10 is an explanatory diagram of a step of stacking paste-applied resin sheets to obtain a laminate as part of the method of manufacturing a resin multilayer substrate according to Embodiment 3 of the present invention. FIG. 10 is a cross-sectional view of a resin multilayer substrate obtained by a method for manufacturing a resin multilayer substrate according to Embodiment 3 of the present invention; FIG. 4 is a cross-sectional view of another example of a resin multilayer substrate;

The dimensional ratios shown in the drawings do not necessarily represent reality, and the dimensional ratios may be exaggerated for convenience of explanation. In the following description, references to the concept of up or down do not necessarily mean absolute up or down, but may mean relative up or down within the postures shown. .

(Embodiment 1)
(composition)
A liquid crystal polymer powder according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 3. FIG.

FIG. 1 shows an enlarged view of an example of the liquid crystal polymer powder according to this embodiment. This is liquid crystal polymer powder 101 . Liquid crystal polymer powder 101 in the present embodiment includes a C═O peak in the C1s peak of the C1s narrow scan spectrum obtained by X-ray photoelectron spectroscopy. FIG. 2 shows an example of the C1s narrow scan spectrum obtained by subjecting the liquid crystal polymer powder 101 to X-ray photoelectron spectroscopy. The C1s peak 61 is shown in FIG. Since the C1s peak 61 is obtained by superimposing a plurality of peaks, if this is further broken down into individual types of peaks, it becomes as shown in FIG. In FIG. 3, the CC, CH peak 62, the OC=O peak 63, the OC peak 64, and the C=O peak 65 appear. The result of superimposing these peaks corresponds to the C1s peak 61 . In FIG. 3, the C1s peak 61 is indicated by a dashed line for reference.

(action/effect)
According to the liquid crystal polymer powder 101 of the present embodiment, it is possible to stably obtain adhesion between the resin layers. Experimental examples conducted by the inventors to confirm this effect will be described below.

(Experimental example)
A liquid crystal polymer powder 1 as shown in FIG. 4 was prepared by sieving a freeze-pulverized liquid crystal polymer film. Liquid crystal polymers are also referred to as "LCPs". 980 g of a mixture of ethanol and pure water at a ratio of 1:4 was prepared. As shown in FIG. 5, 20 g of the liquid crystal polymer powder 1 was added to the mixed liquid 4 and dispersed to prepare a dispersion liquid 5 .

A double-tube ultraviolet irradiation apparatus using a 20 W low-pressure mercury lamp with a main wavelength of 254 nm was prepared. The double-tube structure ultraviolet irradiation device is as shown in an exploded view in FIG. The device comprises an inner layer tube 51 and an outer layer tube 52 . The inner layer tube 51 is a translucent tubular body. Inner tube 51 is made of quartz, for example. The inner layer tube 51 is tubular in the middle and closed at one end. In the example shown in FIG. 6, the closed end of the inner layer tube 51 is hemispherical. 6, the inner layer tube 51 is closed at its lower end and has an opening 51c at its upper end. The outer layer tube 52 has an opening 52c at its upper end. The outer layer tube 52 has a supply port 52a facing sideways at the lower portion of the outer peripheral surface. The outer layer tube 52 has a discharge port 52b directed to the side at the upper part of the outer peripheral surface. As shown in FIG. 6, the inner layer tube 51 is inserted into the outer layer tube 52 through the opening 52c. A rod-shaped ultraviolet light source 10 is inserted into an inner layer tube 51 made of quartz through an opening 51c. The ultraviolet light source 10 is a 20W low pressure mercury lamp. The opening 52c of the outer layer tube 52 is closed by the lid member 53. As shown in FIG. However, the lid member 53 has a through hole in the center. FIG. 7 shows a state in which the ultraviolet irradiation device is actually used after being assembled. Two ultraviolet light sources 10 are arranged inside the inner layer tube 51 . The shape, position, and number of the ultraviolet light source 10, supply port 52a, and discharge port 52b shown in FIGS.

In this ultraviolet irradiation device, as shown in FIG. 7, a double tube structure is realized by an inner layer tube 51 and an outer layer tube 52 . The dispersion liquid 5 (see FIG. 5) is allowed to flow through the gap between the inner layer tube 51 and the outer layer tube 52 . The dispersion liquid 5 is supplied into the outer layer tube 52 from the supply port 52a and discharged from the discharge port 52b, as indicated by an arrow 92 in FIG. Since the ultraviolet light source 10 is arranged inside the inner layer tube 51 which is a translucent member, the ultraviolet light emitted from the ultraviolet light source 10 is transmitted through the inner layer tube 51 and enters the dispersion liquid 5 .

Using this ultraviolet irradiation device, the dispersion liquid 5 was circulated around the ultraviolet light source 10 with a liquid feed pump for 30 minutes. During this time, the liquid crystal polymer powder 1 in the dispersion liquid 5 was surface-treated by being exposed to ultraviolet light. The dispersion liquid 5 was dried to obtain a liquid crystal polymer powder 101 that had been irradiated with ultraviolet rays. This is the liquid crystal polymer powder 101 as shown in FIG.

Here, the time for continuing to circulate the dispersion liquid 5 while being irradiated with ultraviolet light by the ultraviolet irradiation device was set to 30 minutes, but the length of this time (hereinafter referred to as "treatment time") was varied in several ways. , a plurality of liquid crystal polymer powders 101 were obtained. Specifically, the treatment time was 30 minutes, 50 minutes, 100 minutes, and 300 minutes. Treatment times of 30 minutes, 50 minutes, 100 minutes and 300 minutes are hereinafter referred to as Examples 1, 2, 3 and 4, respectively. Further, as comparative examples, a sample with a treatment time of 10 minutes (hereinafter referred to as "comparative example 1") and a sample without such ultraviolet irradiation treatment (hereinafter referred to as "comparative example 2") were prepared. . Therefore, a total of 6 samples of Examples 1 to 4 and Comparative Examples 1 and 2 were prepared. Using these liquid crystal polymer powders prepared as samples, the following items were measured.

(Measurement item 1)
As shown in FIG. 8, liquid crystal polymer powder as a sample and dispersion medium 6 were mixed. Dispersion medium 6 is 180 g of 1,3-butanediol. Here, the sample and the dispersion medium 6 are placed in the container 11 for convenience of explanation. The shape of the container 11 is not limited to that shown here. A paste 7 was obtained as shown in FIG. 9 by sufficiently dispersing the liquid crystal polymer powder. Paste 7 does not contain a binder component. Paste 7 is contained in container 11 . Liquid crystal polymer powder is dispersed in the paste 7 . This paste will be used as a paint.

As shown in FIG. 10, the paste 7 was applied to the surface of the liquid crystal polymer film 41 and dried on a hot plate at 100° C. to prepare a coating film. As shown in FIG. 11, a liquid crystal polymer film 41 and another liquid crystal polymer film 42 were superimposed and thermocompression bonded by hot press to obtain a laminate as shown in FIG. In this laminate, the coating is sandwiched between two liquid crystal polymer films 41,42.

As shown in FIG. 13, this laminate was cut into strips with a width of 5 mm. At this time, the longitudinal direction 91 of the strip shape was made to coincide with the stretching direction when the liquid crystal polymer film as the substrate was initially formed. Using the method of JIS K6854-3 (Adhesive-Peeling adhesive strength test method-Part 3: T-type peeling), peel off at an average speed of 50 mm / min with a tensile tester as shown in FIG. 14, T peel strength asked for The value obtained by dividing the magnitude of the obtained force by the width of the strip, that is, 5 mm, is the T peel strength.

(Measurement item 2)
X-ray photoelectron spectroscopic analysis was performed on the liquid crystal polymer powder. In the obtained C1s narrow scan spectrum, the binding energies of C—C and C—H are normalized to 284.6 eV, and C—C (284.6 eV), C—O (286.4 eV), C=O (286 .8 eV) and OC=O (288.9 eV), and from the peak area of each peak, the ratio of the state of the CO peak and the C=O peak, which is an index of the change, was calculated.

(Measurement item 3)
The obtained liquid crystal polymer powder is compacted at 200 MPa or more using a mold, and the softening temperature is measured with a thermomechanical device using the method of JISK7196 (softening temperature test method by thermomechanical analysis of thermoplastic films and sheets). asked.

Table 1 shows the measurement results of Examples 1-4 and Comparative Examples 1-2 for measurement items 1-3. Table 1 also shows the presence or absence of the C=O peak.

As shown in Table 1, in Example 1, the T peel strength was sufficiently high and sufficient adhesion was obtained. In Example 1, the softening point was greatly lowered because the surface treatment of the liquid crystal polymer powder by ultraviolet light irradiation progressed sufficiently. The lowered softening point makes it easier for the paint layer to melt, increasing the adhesion during hot pressing. These effects are the same not only in the first embodiment but also in the second, third, and fourth embodiments.

As shown in Table 1, in Comparative Example 1, the decrease in softening point was 2°C, which was small. In Comparative Example 1, sufficient adhesion was not obtained. In Comparative Example 1, it seems that the surface treatment of the liquid crystal polymer powder by ultraviolet light irradiation did not proceed sufficiently.

In Comparative Example 2, the liquid crystal polymer powder was not subjected to any surface treatment by ultraviolet light irradiation, so sufficient adhesion was not obtained.

Liquid crystal polymer powder 101 in the present embodiment preferably satisfies the following conditions. 284.6 eV, which is the peak of C—C or C—H when the bond energy of C—C or C—H is normalized to 284.6 eV in the peak that becomes apparent when the C1s peak is split, C =O peak 286.8 eV, CO peak 286.4 eV, O-C=O peak 288.9 eV The ratio of the area occupied by the C=O peak to the total area is 1% or more and less than 10% is preferably The area of each peak is the mountain-shaped area formed by the curve of each peak.

(Embodiment 2)
(composition)
A paste according to Embodiment 2 of the present invention will be described with reference to FIG. An example of this paste is shown in FIG. Paste 201 in the present embodiment contains liquid crystal polymer powder 101 described in the first embodiment and dispersion medium 6 . Liquid crystal polymer powder 101 is dispersed in dispersion medium 6 .

(action/effect)
By using the paste 201 according to the present embodiment as a coating material and applying it to the surface of the resin film, the adhesiveness of the resin film can be improved, as is clear from the experimental results of the first embodiment.

(Embodiment 3)
(Production method)
A method for manufacturing a resin multilayer substrate according to Embodiment 3 of the present invention will be described with reference to FIG. A flow chart of this manufacturing method is shown in FIG.

The method for manufacturing a resin multilayer substrate according to the present embodiment includes step S2 of preparing a paste 201 in which a liquid crystal polymer powder containing a C=O peak in a C1s peak is dispersed in a dispersion medium, and It includes a step S3 of applying the paste 201 to the sheet 2, a step S4 of stacking the resin sheets 2 coated with the paste 201 to obtain a laminate, and a thermocompression bonding step S5 of applying heat and pressure to the laminate. In FIG. 17, a paint layer 8 is formed on the surface of the resin sheet 2 by applying the paste 201 as paint. This manufacturing method may include a step S1 of preparing a liquid crystal polymer powder including a C═O peak in the C1s peak before step S2.

An example of step S4 is shown in FIG. A paint layer 8 is partially formed on the surface of the resin sheet 2 . As shown in FIG. 18, a conductor pattern 17 may be formed so as to partially cover any surface of the resin sheet 2 . In the example shown here, the conductor pattern 17 is formed on the surface opposite to the surface on which the paint layer 8 is formed. The resin sheet 2 may include conductor vias 16 . The conductor vias 16 are provided so as to penetrate the resin sheet 2 .

After completing the thermocompression bonding step S5 on the laminate obtained by stacking a plurality of resin sheets 2 as shown in FIG. 18, a resin multilayer substrate 301 is obtained as shown in FIG. The paint layer 8 becomes the layer 18 by volatilizing the dispersion medium component through the thermocompression bonding step S5. The layer 18 is mainly made of liquid crystal polymer powder. That is, the resin multilayer substrate 301 includes the layer 18 whose main material is the liquid crystal polymer powder as described in the first embodiment.

Although FIG. 19 shows the resin multilayer board 301 including the conductor vias 16, the conductor patterns 17, etc., the present invention is not limited to this, and may be, for example, a resin multilayer board 302 shown in FIG. The resin multilayer board 302 is obtained by laminating and thermally compressing a plurality of resin sheets 2 , and the layer 18 is arranged on a part of the interfaces where the resin sheets 2 are in contact with each other. The layer 18 is based on liquid crystal polymer powder as described above. Layer 18 may be provided for any purpose.

In the resin multilayer substrate 301, the layer 18 preferably has a softening point lower than the softening point of the liquid crystal polymer powder that has not been treated with ultraviolet rays by 4° C. or more and less than 20° C. If the decrease in softening point is less than 4°C, the adhesion is insufficient. If the softening point decreases by 20° C. or more, the material of the layer 18 will flow excessively during the thermocompression bonding step S5, which is undesirable. Therefore, layer 18 preferably has a softening point that is 4° C. or more and less than 20° C. lower than the softening point of the liquid crystal polymer powder that has not been treated with UV light.

The liquid crystal polymer powder can be obtained by crushing a biaxially oriented liquid crystal polymer sheet. The liquid crystal polymer powder may be used as it is after being powdered. The liquid crystal polymer powder may be fibrillated. That is, a paste may be obtained by fibrillating the liquid crystal polymer powder and then dispersing it in a dispersion medium. The paste thus obtained may be applied to a resin film as a paint. A resin multilayer substrate may be obtained by laminating the resin films coated with the paste in this manner.

It should be noted that a plurality of the above embodiments may be appropriately combined and employed.
It should be noted that the above embodiments disclosed this time are illustrative in all respects and are not restrictive. The scope of the present invention is indicated by the claims, and includes all changes within the meaning and range of equivalents to the claims.

1 liquid crystal polymer powder, 2 resin sheet, 4 mixture, 5 dispersion, 6 dispersion medium, 7 paste, 8 paint layer, 10 ultraviolet light source, 11 container, 16 conductor via, 17 conductor pattern, 18 (paint layer is thermocompression layer, 41, 42 liquid crystal polymer film, 51 inner layer tube, 51c opening, 52 outer layer tube, 52a supply port, 52b outlet, 52c opening, 53 lid member, 61 C1s peak, 62 CC, CH peak, 63 O-C=O peak, 64 O-C peak, 65 C=O peak, 91 longitudinal direction, 92 arrow, 101 liquid crystal polymer powder, 201 paste, 301 resin multilayer substrate.

Claims (5)

A liquid crystal polymer powder containing a C=O peak in the C1s peak of the C1s narrow scan spectrum obtained by X-ray photoelectron spectroscopy ,
284.6 eV, which is the peak of C—C or C—H when the bond energy of C—C or C—H is normalized to 284.6 eV in the peaks that become apparent when dividing the C1s peak; The ratio of the area of the C=O peak to the total area of the C=O peak of 286.8 eV, the C—O peak of 286.4 eV, and the O—C=O peak of 288.9 eV is 1% or more and 10%. A liquid crystal polymer powder that is less than A paste comprising the liquid crystal polymer powder according to claim 1 and a dispersion medium, wherein the liquid crystal polymer powder is dispersed in the dispersion medium. A resin multilayer substrate comprising a layer containing the liquid crystal polymer powder according to claim 1 as a main material. 4. The resin multilayer substrate according to claim 3 , wherein said layer has a softening point lower than that of the liquid crystal polymer powder which is not treated with ultraviolet rays by 4[deg.] C. or more and less than 20[deg.] C. A step of preparing a paste according to claim 2 ;
a step of applying the paste to a resin sheet containing a thermoplastic resin as a main material;
a step of stacking the resin sheets coated with the paste to obtain a laminate;
and a thermocompression bonding step of applying heat and pressure to the laminate.

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