JP7494837B2 - Resin composition, resin film and liquid crystal display element - Google Patents

Description

The present invention relates to a transmissive-scattering type liquid crystal display element that is in a scattering state when no voltage is applied and in a transparent state when voltage is applied.

The TN (Twisted Nematic) mode is a type of liquid crystal display element that has been put to practical use. In this mode, a polarizing plate is required to switch light by utilizing the optical rotation properties of liquid crystals. The use of a polarizing plate reduces the efficiency of light utilization.

As a liquid crystal display element that does not use a polarizing plate, there is an element that switches between a transmission state (also called a transparent state) and a scattering state of liquid crystal. Generally, those that use a polymer dispersed liquid crystal (also called a polymer dispersed liquid crystal (PDLC)) or a polymer network liquid crystal (also called a polymer network liquid crystal (PNLC)) are known.
In these liquid crystal display elements, a liquid crystal composition containing a polymerizable compound that is polymerized by ultraviolet light is placed between a pair of substrates equipped with electrodes, and the liquid crystal composition is cured by irradiation with ultraviolet light to form a composite of the liquid crystal and a cured product of the polymerizable compound (e.g., a polymer network). In these liquid crystal display elements, the scattering state and transmission state of the liquid crystal are controlled by application of a voltage.
Among liquid crystal display elements using PDLC or PNLC, there are liquid crystal display elements (also called normal type elements) in which the liquid crystal is randomly oriented when no voltage is applied, resulting in a cloudy (scattered) state, and when a voltage is applied, the liquid crystal is aligned in the direction of the electric field, transmitting light and becoming a transparent state (see Patent Documents 1 and 2). In this case, since the liquid crystal is random when no voltage is applied, there is no need for a liquid crystal alignment film or alignment treatment to align the liquid crystal in one direction. Therefore, in this liquid crystal display element, the electrodes and the liquid crystal layer (a composite of the liquid crystal and a cured product of a polymerizable compound) are in direct contact with each other (see Patent Documents 1 and 2).

Japanese Patent No. 3552328 Japanese Patent No. 4630954

The polymerizable compound in the liquid crystal composition has the role of forming a polymer network to obtain the desired optical characteristics and to increase the adhesion between the liquid crystal layer and the electrodes. However, in order to achieve this, it is necessary to form a dense polymer network, which inhibits the driving of the liquid crystal molecules in response to the application of voltage. As a result, this element has a higher driving voltage than liquid crystal display elements such as TN mode.

In view of the above, the present invention aims to provide a liquid crystal display element that exhibits good optical characteristics and requires a low driving voltage.

As a result of intensive research by the inventors in order to achieve the above object, the present invention has been completed as described below.
That is, the present invention provides a transmissive-scattering liquid crystal display element, which has a liquid crystal layer obtained by applying at least one of active energy rays and heat to a liquid crystal composition containing a liquid crystal and a polymerizable compound and disposed between a pair of substrates each having an electrode, and which is cured by applying at least one of active energy rays and heat to the liquid crystal composition, and which has a resin film on at least one of the substrates, and which is in a scattering state when no voltage is applied and in a transparent state when a voltage is applied,
The liquid crystal display element is characterized in that the resin film is obtained using a resin composition containing a polymer having at least one structure (also referred to as specific structure (1)) selected from the following formulas [1-1] and [1-2]:

^X1 represents a single bond, -( _CH2 ) _a- (a is an integer of 1 to 15), -O-, _-CH2O- , -CONH-, -NHCO-, -CON( _CH3 )-, -N( _CH3 )CO-, -COO- or -OCO-. ^X2 represents a single bond or -( _CH2 ) _b- (b is an integer of 1 to 15). ^X3 represents a single bond, -( _CH2 ) _c- (c is an integer of 1 to 15), -O-, _-CH2O- , -COO- or -OCO-. ^X4 represents a divalent cyclic group selected from a benzene ring, a cyclohexane ring, and a heterocycle, or a divalent organic group having 17 to 51 carbon atoms and a steroid skeleton, and any hydrogen atom on the cyclic group may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom. ^X5 represents a divalent cyclic group selected from a benzene ring, a cyclohexane ring, and a heterocycle, and any hydrogen atom on these cyclic groups may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom. Xn represents an integer of 0 to 4. ^X6 represents an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, or a fluorine-containing alkoxy group having 1 to 18 carbon atoms.

^X7 represents a single bond, -O-, _-CH2O- , -CONH-, -NHCO-, -CON( _CH3 )-, -N( _CH3 )CO-, -COO- or -OCO-, and ^X8 represents an alkyl group having 8 to 22 carbon atoms or a fluorine-containing alkyl group having 6 to 18 carbon atoms.

According to the present invention, a liquid crystal display element having good optical characteristics and requiring a low driving voltage can be obtained.
The mechanism by which the present invention provides a liquid crystal display device having the above-mentioned excellent characteristics is not entirely clear, but is presumed to be as follows.
The specific structure (1) has a moiety such as a benzene ring or a cyclohexane ring, and a long-chain alkyl group, and therefore it is believed that a resin film obtained from a resin composition containing the specific structure (1) can promote the driving of liquid crystal when a voltage is applied, and can reduce the driving voltage of a liquid crystal display element.
In addition, since the structure of the formula [1-1] is a rigid structure, the above-mentioned effect can be obtained even with a small amount of use, and therefore the hydrophobic structure on the resin film can be reduced, so that the adhesion between the liquid crystal layer and the resin film in the liquid crystal display element can be improved, thereby improving the reliability of the liquid crystal display element.
Thus, a liquid crystal display element using a resin composition containing a polymer having the specific structure (1) has the above-mentioned characteristics. Therefore, the liquid crystal display element of the present invention can be used as a liquid crystal display for display purposes, a light control window or an optical shutter element for controlling the blocking and transmission of light, etc.

<Specific structure (1)>
The specific structure (1) is a structure represented by the above formula [1-1] or [1-2].
In the formula [1-1], X ¹ to X ⁶ and Xn are as defined above, and among them, the following are preferable.
From the viewpoints of availability of raw materials and ease of synthesis, ^X1 is preferably a single bond, -(CH ₂ ) _a - (a is an integer of 1 to 15), -O-, -CH ₂ O- or -COO-, and more preferably a single bond, -(CH ₂ ) _a - (a is an integer of 1 to 10), -O-, -CH ₂ O- or -COO-.
X ² is preferably a single bond or —(CH ₂ ) _b — (b is an integer of 1 to 10).
From the viewpoint of ease of synthesis, ^X3 is preferably a single bond, -( _CH2 ) _a- (a is an integer of 1 to 15), -O-, _-CH2O- or -COO-, more preferably a single bond, -( _CH2 ) _a- (a is an integer of 1 to 10), -O-, _-CH2O- or -COO-.
From the viewpoint of ease of synthesis, ^X4 is preferably an organic group having 17 to 51 carbon atoms and having a benzene ring, a cyclohexane ring, or a steroid skeleton.
^X5 is preferably a benzene ring or a cyclohexane ring.
^X6 is preferably an alkyl group having 1 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, or a fluorine-containing alkoxy group having 1 to 10 carbon atoms. More preferably, it is an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms. Particularly preferably, it is an alkyl group having 1 to 9 carbon atoms or an alkoxy group having 1 to 9 carbon atoms.
From the viewpoints of availability of raw materials and ease of synthesis, Xn is preferably an integer of 0 to 3, and more preferably an integer of 0 to 2.

Preferred combinations of X ¹ to X ⁶ and Xn include the same combinations as those in (2-1) to (2-629) listed in Tables 6 to 47 on pages 13 to 34 of International Publication WO2011/132751 (published on October 27, 2011). In each table of the International Publication, X ¹ to X ⁶ in the present invention are shown as Y1 to Y6, and Xn is shown as n, but Y1 to Y6 should be read as X ¹ to X ⁶ , and n should be read as Xn. In addition, in (2-605) to (2-629) listed in each table of the International Publication, the organic group having 17 to 51 carbon atoms and a steroid skeleton in the present invention is shown as an organic group having 12 to 25 carbon atoms and a steroid skeleton, but the organic group having 12 to 25 carbon atoms and a steroid skeleton should be read as an organic group having 17 to 51 carbon atoms and a steroid skeleton.

Among them, the combinations (2-25) to (2-96), (2-145) to (2-168), (2-217) to (2-240), (2-268) to (2-315), (2-364) to (2-387), (2-436) to (2-483), or (2-603) to (2-615) are preferred. Particularly preferred are the combinations (2-49) to (2-96), (2-145) to (2-168), (2-217) to (2-240), (2-603) to (2-606), (2-607) to (2-609), (2-611), (2-612), or (2-624).

In the formula [1-2], X ⁷ and X ⁸ are as defined above, and among them, the following are preferable.

X ⁷ is preferably a single bond, —O—, —CH ₂ O—, —CONH—, —CON(CH ₃ )— or —COO—, more preferably a single bond, —O—, —CONH— or —COO—.
^X8 is preferably an alkyl group having 8 to 18 carbon atoms.

As described above, the specific structure (1) in the present invention preferably has the structure of the formula [1-1], since the driving voltage of the liquid crystal display element can be more efficiently reduced.
The specific structure (1) is preferably contained in a repeating unit constituting the polymer. The repeating unit containing the specific structure (1) is preferably contained in an amount of 0.1 to 60 mol %, more preferably 1 to 30 mol %, based on the total repeating units constituting the polymer.
<Specific structure (2)>
The polymer in the present invention preferably further has at least one structure selected from the following formulae [2-a] to [2-i] (also referred to as specific structure (2)).

Y ^A represents a hydrogen atom or a benzene ring.
Among them, the formulae [2-a] to [2-f] are preferable. The formulae [2-a] to [2-e] are more preferable. From the viewpoint of adhesion between the liquid crystal layer and the resin film, the formulae [2-a], [2-b], [2-d], and [2-e] are particularly preferable.
The resin composition of the present invention preferably further contains a polymer having a specific structure (2).
It is considered that the use of specific structure (2) photoreacts with a reactive group of a polymerizable compound in a liquid crystal composition during the process of ultraviolet irradiation or heating in producing a liquid crystal display element, thereby strengthening the adhesion between the liquid crystal layer and the resin film.
<Polymer>
The polymer is not particularly limited, but is preferably at least one polymer selected from the group consisting of acrylic polymers, methacrylic polymers, novolac resins, polyhydroxystyrenes, polyimide precursors, polyimides, polyamides, polyesters, cellulose, and polysiloxanes, and more preferably polyimide precursors, polyimides, or polysiloxanes.
When a polyimide precursor or polyimide (collectively referred to as a polyimide-based polymer) is used as the polymer, it is preferable that the polyimide precursor or polyimide is obtained by reacting a diamine component with a tetracarboxylic acid component.

A polyimide precursor has the structure of the following formula [A].

^R1 represents a tetravalent organic group. ^R2 represents a divalent organic group. ^A1 and ^A2 each represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. ^A3 and ^A4 each represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or an acetyl group. n represents a positive integer.

The diamine component is a diamine having two primary or secondary amino groups in the molecule, and the tetracarboxylic acid component is a tetracarboxylic acid compound, a tetracarboxylic acid dianhydride, a tetracarboxylic acid dihalide compound, a tetracarboxylic acid dialkyl ester compound, or a tetracarboxylic acid dialkyl ester dihalide compound.

Polyimide-based polymers are preferably polyamic acid having a repeating unit structural formula of the following formula [D] or polyimide obtained by imidizing said polyamic acid, because they can be obtained relatively easily by using as raw materials a tetracarboxylic dianhydride of the following formula [B] and a diamine of the following formula [C].

R ¹ and R ² are the same as defined in formula [A].

R ¹ and R ² are the same as defined in formula [A].

Furthermore, the alkyl groups having 1 to 8 carbon atoms as ^A1 and ^A2 in formula [A], and the alkyl groups having 1 to 5 carbon atoms or acetyl groups as ^A3 and ^A4 in formula [A] can also be introduced into the polymer of formula [D] obtained above by a normal synthesis method.
As a method for introducing the specific structure (1) into a polyimide polymer, it is preferable to use a diamine having the specific structure (1) as a part of a raw material. In particular, it is preferable to use a diamine having at least one structure selected from the above formulas [1-1] and [1-2] (also referred to as specific diamine (1)).

In particular, it is preferable to use a diamine of the following formula [1a]:

X represents the formula [1-1] or [1-2]. Details of X ¹ to X ⁶ and Xn in the formula [1-1] and preferred combinations thereof are as in the formula [1-1], and details of X ⁷ and X ⁸ in the formula [1-2] and preferred combinations thereof are as in the formula [1-2].
Xm represents an integer of 1 to 4. Of these, 1 or 2 is preferred.
Specific examples of the specific diamine (1) of formula [1-1] include diamine compounds of formulas [2-1] to [2-6] and formulas [2-9] to [2-36] described on pages 15 to 19 of International Publication WO2013/125595 (published on August 29, 2013). In the description of International Publication WO2013/125595, R ₂ in formulas [2-1] to [2-3] and R ₄ in formulas [2-4] to [2-6] represent an alkyl group having 1 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, or a fluorine-containing alkoxy group having 1 to 18 carbon atoms. In addition, A ₄ in formula [2-13] represents a linear or branched alkyl group having 3 to 18 carbon atoms. In addition, R ₃ in the formulas [2-4] to [2-6] represents —O—, —CH ₂ O—, —COO— or —OCO—.

Among them, preferred diamines are the diamine compounds of the formulas [2-1] to [2-6], [2-9] to [2-13], or [2-22] to [2-31] described in International Publication WO2013/125595.
More preferred from the viewpoint of the optical properties of the liquid crystal display element are the diamines of the following formulae [1a-32] to [1a-41].

^R1 and ^R2 each represent an alkyl group having 3 to 12 carbon atoms.

^R3 and ^R4 each represent an alkyl group having 3 to 12 carbon atoms, and the cis-trans isomerism of 1,4-cyclohexylene is a trans isomer.
From the viewpoint of the optical properties of the liquid crystal display device, the diamines of the above formulas [1a-35] to [1a-37], [1a-40] and [1a-41] are most preferred.
Specific examples of the specific diamine (1) of formula [1-2] include diamine compounds of formulas [DA1] to [DA11] described in International Publication WO2013/125595 (published on August 29, 2013), page 23. In the description of International Publication WO2013/125595, A ₁ in formulas [DA1] to [DA5] represents an alkyl group having 8 to 22 carbon atoms or a fluorine-containing alkyl group having 6 to 18 carbon atoms.
The proportion of the specific diamine (1) used is preferably 0.1 to 60 mol % relative to the total diamine components from the viewpoints of the optical characteristics of the liquid crystal display element and the adhesion between the liquid crystal layer and the resin film, and more preferably 1 to 30 mol %. The specific diamine (1) may be used alone or in combination of two or more kinds depending on the respective characteristics.
As a method for introducing the specific structure (2) into a polyimide polymer, it is preferable to use a diamine having the specific structure (2) as a part of a raw material. In particular, it is preferable to use a diamine having the structure of the following formula [2] (also referred to as specific diamine (2)).

^Y1 represents a single bond, -O-, -NH-, -N( _CH3 )-, -CH2O-, -CONH-, -NHCO-, -CON( _CH3 )-, -N( _CH3 )CO-, -COO- or -OCO-. Of these, a single bond, -O-, _-CH2O- , -CONH-, -COO- or -OCO- is preferred. From the viewpoint of availability of raw materials and ease _of synthesis, a single bond, -O-, _-CH2O- or -COO- is more preferred.
^Y2 represents a single bond, an alkylene group having 1 to 18 carbon atoms, or an organic group having 6 to 24 carbon atoms and having a cyclic group selected from a benzene ring, a cyclohexane ring, and a heterocycle, and any hydrogen atom on these cyclic groups may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom. Among these, a single bond, an alkylene group having 1 to 12 carbon atoms, a benzene ring, or a cyclohexane ring is preferred. From the viewpoint of adhesion between the liquid crystal layer and the resin film, a single bond or an alkylene group having 1 to 12 carbon atoms is more preferred.
^Y3 represents a single bond, _-O- , -NH-, -N( _CH3 )-, -CH2O-, -CONH-, -NHCO-, -CON( _CH3 )-, -N( _CH3 )CO-, -COO- or -OCO-. Of these, a single bond, -O-, -COO- or -OCO- is preferred. A single bond or -OCO- is more preferred.
^Y4 represents at least one structure selected from the formulas [2-a] to [2-i]. Among them, the formulas [2-a] to [2-f] are preferred. More preferred are the formulas [2-a] to [2-e]. From the viewpoint of adhesion between the liquid crystal layer and the resin film, the formulas [2-a], [2-b], [2-d], and [2-e] are particularly preferred.
Yn represents an integer of 1 to 4. Of these, 1 or 2 is preferred.

It is preferable to use a diamine of the following formula [2a] as the specific diamine (2).

Y represents a structure of the above formula [2]. Details of Y ¹ to Y ⁴ and Yn in the formula [2] and preferred combinations are as in the above formula [2].
Ym represents an integer of 1 to 4. Of these, 1 is preferred.

More specific examples of the specific diamine (2) include those represented by the following formulas [2a-1] to [2a-12], and it is preferable to use these.

n1 represents an integer from 2 to 12.

n2 represents an integer from 0 to 12. n3 represents an integer from 2 to 12.

Among them, the formulas [2a-1], [2a-2], [2a-5] to [2a-7], [2a-11] and [2a-12] are preferred. The formulas [2a-5] to [2a-7], [2a-11] and [2a-12] are more preferred.
The proportion of the specific diamine (2) used is preferably 5 to 70 mol % relative to the total diamine components from the viewpoints of the optical characteristics of the liquid crystal display element and the adhesion between the liquid crystal layer and the resin film, and more preferably 10 to 60 mol %. The specific diamine (2) may be used alone or in combination of two or more kinds depending on the respective characteristics.
As the diamine component for producing the polyimide polymer, diamines other than the specific diamine (1) and the specific diamine (2) (also referred to as other diamines) can also be used.

Specific examples include other diamine compounds described on pages 27 to 30 of International Publication WO2015/012368 (published on January 29, 2015), and diamine compounds of formulae [DA1] to [DA14] described on pages 30 to 32 of the same publication. In addition, the other diamines can be used alone or in combination of two or more depending on the properties of each compound.

In the present invention, it is preferable to use both the specific diamine (1) and the specific diamine (2) in terms of the optical characteristics of the liquid crystal display element and the adhesion between the liquid crystal layer and the resin film.
As the tetracarboxylic acid component for producing the polyimide polymer, it is preferable to use a tetracarboxylic acid dianhydride represented by the following formula [3], or a derivative thereof, such as a tetracarboxylic acid, a tetracarboxylic acid dihalide, a tetracarboxylic acid dialkyl ester, or a tetracarboxylic acid dialkyl ester dihalide (all of which are also collectively referred to as a specific tetracarboxylic acid component).

Z represents any of the following formulas [3a] to [3l].

Z ^A to Z ^D each represent a hydrogen atom, a methyl group, a chlorine atom, or a benzene ring. Z ^E and Z ^F each represent a hydrogen atom or a methyl group.
Among them, Z in formula [3] is preferably formula [3a], formula [3c], formula [3d], formula [3e], formula [3f], formula [3g], formula [3k] or formula [3l] in terms of ease of synthesis and ease of polymerization reactivity when producing a polymer. More preferred are formula [3a], formula [3e], formula [3f], formula [3g], formula [3k] or formula [3l]. Particularly preferred are formula [3a], formula [3e], formula [3f], formula [3g] or formula [3l] in terms of optical properties of a liquid crystal display element.
The proportion of the specific tetracarboxylic acid component used is preferably 1 mol % or more, more preferably 5 mol % or more, and particularly preferably 10 mol % or more, based on the total tetracarboxylic acid components. From the viewpoint of the optical properties of the liquid crystal display element, the most preferred proportion is 10 to 90 mol %.

The polyimide polymer may contain tetracarboxylic acid components other than the specific tetracarboxylic acid component, such as the following tetracarboxylic acid compounds, tetracarboxylic dianhydrides, dicarboxylic acid dihalide compounds, dicarboxylic acid dialkyl ester compounds, and dialkyl ester dihalide compounds.
Specific examples of the tetracarboxylic acid components include those described on pages 34 to 35 of International Publication WO2015/012368 (published on January 29, 2015).
The specific tetracarboxylic acid component and the other tetracarboxylic acid components may be used alone or in combination of two or more depending on the respective properties.
The method for synthesizing the polyimide polymer is not particularly limited. Usually, the polyimide polymer is obtained by reacting a diamine component with a tetracarboxylic acid component. Specifically, the method described on pages 35 to 36 of International Publication WO2015/012368 (published on January 29, 2015) can be mentioned.

The reaction between the diamine component and the tetracarboxylic acid component is usually carried out in a solvent containing the diamine component and the tetracarboxylic acid component. There are no particular limitations on the solvent used, as long as it dissolves the resulting polyimide precursor.

Specific examples include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, and 1,3-dimethyl-2-imidazolidinone. In addition, when the polyimide precursor has high solvent solubility, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or the solvents of the following formulae [D1] to [D3] can be used.

^D1 and ^D2 each represent an alkyl group having 1 to 3 carbon atoms. ^D3 represents an alkyl group having 1 to 4 carbon atoms.
These may be used alone or in combination. Furthermore, even if the solvent does not dissolve the polyimide precursor, it may be mixed with the solvent to the extent that the generated polyimide precursor does not precipitate. Furthermore, since moisture in the organic solvent inhibits the polymerization reaction and further causes hydrolysis of the generated polyimide precursor, it is preferable to use an organic solvent that has been dehydrated and dried.
In the polymerization reaction of the polyimide precursor, the total number of moles of the tetracarboxylic acid components when the total number of moles of the diamine components is 1.0 is preferably 0.8 to 1.2. When the total number of moles of the tetracarboxylic acid components is smaller than 1.0, that is, when the total number of moles of the tetracarboxylic acid components is smaller than the number of moles of the diamine components, the polymer ends in an amino group structure, and when the total number of moles of the tetracarboxylic acid components is larger than the number of moles of the diamine components, the polymer ends in a carboxylic anhydride or dicarboxylic acid structure. In the present invention, since the effect of the specific compound is higher, it is preferable that the total number of moles of the tetracarboxylic acid components is larger than 1.0, that is, the total number of moles of the tetracarboxylic acid components is larger than the number of moles of the diamine components. Specifically, when the total number of moles of the diamine components is 1.0, it is preferable that the total number of moles of the tetracarboxylic acid components is 1.05 to 1.20.

Polyimide is obtained by ring-closing a polyimide precursor. In this polyimide, the ring-closure rate of the amic acid group (also called the imidization rate) does not necessarily have to be 100%, and can be adjusted as desired depending on the application and purpose. In particular, from the viewpoint of the solubility of the polyimide polymer in a solvent, a rate of 30 to 80% is preferable. A rate of 40 to 70% is even more preferable.

Considering the strength of the resin film obtained therefrom, and the workability and coating properties during the formation of the resin film, the molecular weight of the polyimide polymer is preferably 5,000 to 1,000,000 in terms of Mw (weight average molecular weight) measured by GPC (Gel Permeation Chromatography), and more preferably 10,000 to 150,000.
When a polysiloxane is used for the polymer, it is preferable to use a polysiloxane obtained by polycondensing an alkoxysilane of the following formula [A1], or a polysiloxane obtained by polycondensing the alkoxysilane of the formula [A1] with an alkoxysilane of the following formula [A2] and/or formula [A3] (collectively referred to as a polysiloxane-based polymer).
Alkoxysilane of formula [A1]:

A ¹ represents the formula [1-1] or [1-2]. Details of X ¹ to X ⁶ and Xn in the formula [1-1] and preferred combinations are as in the formula [1-1], and details of X ⁷ and X ⁸ in the formula [1-2] and preferred combinations are as in the formula [1-2]. Of these, it is preferable to use the structure of the formula [1-1], since it is possible to more efficiently lower the driving voltage of the liquid crystal display element.
^A2 represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, of which a hydrogen atom or an alkyl group having 1 to 3 carbon atoms is preferred.
^A3 represents an alkyl group having 1 to 5 carbon atoms. Among them, from the viewpoint of reactivity in polycondensation, an alkyl group having 1 to 3 carbon atoms is preferred.
m represents an integer of 1 or 2. Among these, 1 is preferred from the viewpoint of ease of synthesis.
n represents an integer of 0 to 2.
p represents an integer of 0 to 3. Among them, from the viewpoint of reactivity in polycondensation, it is preferably 1 to 3, and more preferably 2 or 3.
m+n+p is 4.

Specific examples of the alkoxysilane of formula [A1] include alkoxysilanes of formula [2a-1] to formula [2a-32] described in International Publication WO2015/008846 (published on January 22, 2015), pages 17 to 21. Among them, alkoxysilanes of formula [2a-9] to formula [2a-21], formula [2a-25] to formula [2a-28], or formula [2a-32] in the same publication are preferred.
The alkoxysilane of the formula [A1] can be used alone or in combination of two or more kinds depending on the respective properties.
Alkoxysilane of formula [A2]:

^B1 represents an organic group having 2 to 12 carbon atoms and having at least one group selected from a vinyl group, an epoxy group, an amino group, a mercapto group, an isocyanate group, a methacryl group, an acryl group, a ureido group, and a cinnamoyl group. Among these, from the viewpoint of availability, an organic group having a vinyl group, an epoxy group, an amino group, a methacryl group, an acryl group, or a ureido group is preferred. An organic group having a methacryl group, an acryl group, or a ureido group is more preferred.
^B2 represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, of which a hydrogen atom or an alkyl group having 1 to 3 carbon atoms is preferred.
^B3 represents an alkyl group having 1 to 5 carbon atoms. Among them, from the viewpoint of reactivity in polycondensation, an alkyl group having 1 to 3 carbon atoms is preferred.
m represents an integer of 1 or 2. Among these, 1 is preferred from the viewpoint of ease of synthesis.
n represents an integer of 0 to 2.
p represents an integer of 0 to 3. Among them, from the viewpoint of reactivity in polycondensation, 1 to 3 is preferable, and 2 or 3 is more preferable.
m+n+p is 4.

Specific examples of the alkoxysilane of the formula [A2] include specific examples of the alkoxysilane of the formula [2b] described on pages 21 to 24 of International Publication WO2015/008846 (published on January 22, 2015).
Among these, allyltriethoxysilane, allyltrimethoxysilane, diethoxymethylvinylsilane, dimethoxymethylvinylsilane, triethoxyvinylsilane, vinyltrimethoxysilane, vinyltris(2-methoxyethoxy)silane, 3-(triethoxysilyl)propyl methacrylate, 3-(trimethoxysilyl)propyl acrylate, 3-(trimethoxysilyl)propyl methacrylate, 3-glycidyloxypropyl(dimethoxy)methylsilane, 3-glycidyloxypropyl(diethoxy)methylsilane, 3-glycidyloxypropyltrimethoxysilane, or 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane is preferred.

The alkoxysilanes of formula [A2] may be used alone or in a mixture of two or more types depending on the respective characteristics.

Alkoxysilane of formula [A3]:

^D1 represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, of which a hydrogen atom or an alkyl group having 1 to 3 carbon atoms is preferred.
^D2 represents an alkyl group having 1 to 5 carbon atoms. Among them, from the viewpoint of reactivity in polycondensation, an alkyl group having 1 to 3 carbon atoms is preferred.
n represents an integer of 0 to 3.

Specific examples of alkoxysilanes of formula [A3] include specific examples of alkoxysilanes of formula [2c] described on pages 24 to 25 of International Publication WO2015/008846 (published on January 22, 2015).

In addition, in formula [A3], examples of alkoxysilanes in which n is 0 include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane, and it is preferable to use these alkoxysilanes as the alkoxysilane of formula [A3].

The alkoxysilane of the formula [A3] can be used alone or in combination of two or more kinds depending on the respective properties.
The polysiloxane polymer is a polysiloxane obtained by polycondensing an alkoxysilane of the formula [A1], or a polysiloxane obtained by polycondensing an alkoxysilane of the formula [A1] with an alkoxysilane of the formula [A2] and/or the formula [A3]. That is, the polysiloxane polymer is any one of a polysiloxane obtained by polycondensing only an alkoxysilane of the formula [A1], a polysiloxane obtained by polycondensing two kinds of alkoxysilanes of the formula [A1] and the formula [A2], a polysiloxane obtained by polycondensing two kinds of alkoxysilanes of the formula [A1] and the formula [A3], and a polysiloxane obtained by polycondensing three kinds of alkoxysilanes of the formula [A1], the formula [A2], and the formula [A3].

Among these, polysiloxanes obtained by polycondensing multiple types of alkoxysilanes are preferred in terms of the reactivity of the polycondensation and the solubility of the polysiloxane-based polymer in a solvent. That is, it is preferred to use any one of the polysiloxanes obtained by polycondensing two types of alkoxysilanes of the formulas [A1] and [A2], the polysiloxanes obtained by polycondensing two types of alkoxysilanes of the formulas [A1] and [A3], and the polysiloxanes obtained by polycondensing three types of alkoxysilanes of the formulas [A1], [A2], and [A3].

When multiple types of alkoxysilanes are used in preparing a polysiloxane-based polymer, the proportion of the alkoxysilane of formula [A1] used in all alkoxysilanes is preferably 0.1 to 60 mol %, more preferably 1 to 30 mol %. Furthermore, the proportion of the alkoxysilane of formula [A2] used in all alkoxysilanes is preferably 5 to 70 mol %, more preferably 10 to 60 mol %. Furthermore, the proportion of the alkoxysilane of formula [A3] used in all alkoxysilanes is preferably 1 to 99 mol %, more preferably 1 to 80 mol %.
The method for polycondensing the polysiloxane polymer is not particularly limited. Specific examples include the methods described on pages 26 to 29 of International Publication WO2015/008846 (published on January 22, 2015).

In the polycondensation reaction for producing a polysiloxane-based polymer, when multiple types of alkoxysilanes of the formula [A1], [A2], or [A3] are used, the multiple types of alkoxysilanes may be reacted using a mixture prepared in advance, or the multiple types of alkoxysilanes may be reacted while being added sequentially.
In the present invention, the solution of the polysiloxane polymer obtained by the above method may be used as a polymer as it is, or, if necessary, the solution of the polysiloxane polymer obtained by the above method may be concentrated, diluted by adding a solvent, or substituted with another solvent, and then used as a polymer.

The solvent used for dilution (also called the additive solvent) may be the solvent used in the polycondensation reaction or other solvents. The additive solvent is not particularly limited as long as the polysiloxane polymer is uniformly dissolved, and one or more types can be selected as desired. In addition to the solvent used in the polycondensation reaction, examples of the additive solvent include ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, and ester solvents such as methyl acetate, ethyl acetate, and ethyl lactate.

Furthermore, when a polysiloxane-based polymer and another polymer are used as the polymer, it is preferable to distill off alcohol generated during the polycondensation reaction of the polysiloxane-based polymer under normal pressure or reduced pressure before mixing the other polymer with the polysiloxane-based polymer.
<Resin Composition>
The resin composition contains a polymer having a specific structure (1), and is preferably a solution for forming a resin film, which contains a polymer having a specific structure (1) and a solvent. In this case, two or more types of polymers having a specific structure (1) can be used.
The concentration of the polymer having the specific structure (1) in the resin composition is preferably from 10 to 100% by mass, more preferably from 20 to 100% by mass, and particularly preferably from 30 to 100% by mass.

All of the polymer components contained in the resin composition may be polymers having the specific structure (1), but in the present invention, as described above, it is preferable that the polymer has both the characteristic structure (1) and the specific structure (2). In that case, one type of polymer having both the specific structure (1) and the specific structure (2) may be used, or a polymer having the specific structure (1) and a polymer having the specific structure (2) may be used in combination. When used in combination, the proportion of the polymer having the specific structure (2) is preferably 10 to 400 parts by mass per 100 parts by mass of the polymer having the specific structure (1). More preferably, it is 50 to 200 parts by mass. One or more types of polymers having the specific structure (2) can be used depending on the characteristics.

The polymer component may also be a mixture of polymers other than the polymer having the specific structure (1) and the polymer having the specific structure (2). In this case, the proportion of the polymer not having a specific structure used is preferably 10 to 200 parts by mass per 100 parts by mass of all the polymers having the specific structures. More preferably, it is 10 to 100 parts by mass.

The content of the solvent in the resin composition can be appropriately selected from the viewpoints of the application method of the resin composition and obtaining the desired film thickness. In particular, from the viewpoint of forming a uniform resin film by application, the content of the solvent in the resin composition is preferably 50 to 99.9% by mass. More preferably, it is 60 to 99% by mass. Especially preferably, it is 65 to 99% by mass.

The solvent used in the resin composition is not particularly limited as long as it dissolves the polymer having a specific structure. In particular, when the polymer is a polyimide precursor, polyimide, polyamide, or polyester, or when the solubility of an acrylic polymer, a methacrylic polymer, a novolac resin, polyhydroxystyrene, cellulose, or a polysiloxane in a solvent is low, it is preferable to use the following solvent (also called solvent type A).

For example, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, etc. Among these, it is preferable to use N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, or γ-butyrolactone. These may be used alone or in combination.

When the polymer is an acrylic polymer, a methacrylic polymer, a novolac resin, polyhydroxystyrene, cellulose or a polysiloxane, or when the polymer is a polyimide precursor, a polyimide, a polyamide or a polyester and these polymers have high solubility in the solvent, the following solvents (also called solvent type B) can be used.

Specific examples of the solvent B include the solvent B described in International Publication WO2014/171493 (published on October 23, 2014), pages 58 to 60. Among them, it is preferable to use 1-hexanol, cyclohexanol, 1,2-ethanediol, 1,2-propanediol, propylene glycol monobutyl ether, ethylene glycol monobutyl ether, dipropylene glycol dimethyl ether, cyclohexanone, cyclopentanone, or the solvents represented by the formulae [D1] to [D3].
When using these solvents B, it is preferable to use them in combination with N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ-butyrolactone of the solvents A, in order to improve the coatability of the resin composition. It is more preferable to use γ-butyrolactone in combination.

These solvents B can improve the coating properties and surface smoothness of the resin film when the resin composition is applied, and therefore, when a polyimide precursor, polyimide, polyamide or polyester is used as the polymer, it is preferable to use the solvents B in combination with the solvents A. In this case, the solvent B is preferably used in an amount of 1 to 99% by mass of the total solvent contained in the resin composition. Of these, 10 to 99% by mass is preferable. More preferably, it is used in an amount of 20 to 95% by mass.
In order to increase the strength of the resin film, it is preferable to introduce into the resin composition a compound having at least one selected from an epoxy group, an isocyanate group, an oxetane group, a cyclocarbonate group, a hydroxy group, a hydroxyalkyl group, and a lower alkoxyalkyl group (collectively referred to as a specific crosslinking compound). In this case, it is necessary for the compound to have two or more of these groups.
Specific examples of the crosslinkable compound having an epoxy group or an isocyanate group include the crosslinkable compounds having an epoxy group or an isocyanate group described on pages 63 to 64 of International Publication WO2014/171493 (published on October 23, 2014).

Specific examples of crosslinkable compounds having an oxetane group include the crosslinkable compounds of formula [4a] to [4k] listed on pages 58 to 59 of International Publication WO2011/132751 (published October 27, 2011).

Specific examples of crosslinkable compounds having a cyclocarbonate group include the crosslinkable compounds of formulas [5-1] to [5-42] listed on pages 76 to 82 of International Publication WO2012/014898 (published on February 2, 2012).

Specific examples of crosslinkable compounds having a hydroxyl group, a hydroxyalkyl group, and a lower alkoxyalkyl group include the melamine derivatives or benzoguanamine derivatives described on pages 65 to 66 of International Publication WO 2014/171493 (published on October 23, 2014), and the crosslinkable compounds of formulas [6-1] to [6-48] described on pages 62 to 66 of International Publication WO 2011/132751 (published on October 27, 2011).

The proportion of the specific crosslinking compound in the resin composition is preferably 0.1 to 100 parts by mass relative to 100 parts by mass of all polymer components. More preferably, it is 0.1 to 50 parts by mass in order to allow the crosslinking reaction to proceed and to exhibit the desired effect. Particularly preferably, it is 1 to 30 parts by mass.
It is preferable to incorporate at least one type of generator (also referred to as a specific generator) selected from a photoradical generator, a photoacid generator, and a photobase generator into the resin composition.

Specific examples of the specific generator include those described in International Publication No. 2014/171493 (published on October 23, 2014), pages 54 to 56. Among them, it is preferable to use a photoradical generator as the specific generator from the viewpoint of adhesion between the liquid crystal layer and the resin film.
The resin composition may contain a compound that improves the uniformity of the thickness of the resin film and the surface smoothness when the resin composition is applied. In addition, a compound that improves the adhesion between the resin film and the substrate may also be used.
Compounds that improve the uniformity of the thickness and surface smoothness of the resin film include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants. Specific examples include surfactants described on page 67 of International Publication WO2014/171493 (published on October 23, 2014). The proportion of the surfactant used is preferably 0.01 to 2 parts by mass relative to 100 parts by mass of all polymer components. More preferably, the proportion is 0.01 to 1 part by mass.

Specific examples of compounds that improve the adhesion between the resin film and the substrate include the compounds described on pages 67 to 69 of International Publication WO2014/171493 (published October 23, 2014). The preferred usage ratio is 0.1 to 30 parts by mass per 100 parts by mass of all polymer components. More preferred is 1 to 20 parts by mass.

In addition to the compounds other than those mentioned above, the resin composition may contain a dielectric or conductive substance for the purpose of changing the electrical properties, such as the dielectric constant and electrical conductivity, of the resin film.
<Liquid Crystal Composition>
The liquid crystal composition includes a liquid crystal and a polymerizable compound.
The liquid crystal may be a nematic liquid crystal, a smectic liquid crystal, or a cholesteric liquid crystal. In particular, it is preferable to use a liquid crystal having positive dielectric anisotropy for the liquid crystal display element of the present invention. In this case, from the viewpoint of low-voltage driving and scattering characteristics, it is preferable to use a liquid crystal having a large anisotropy of dielectric constant and a large anisotropy of refractive index. In addition, the liquid crystal may be a mixture of two or more types of liquid crystals depending on the physical property values of the phase transition temperature, the dielectric anisotropy, and the refractive index anisotropy.
In order to operate a liquid crystal display element as an active element such as a TFT (Thin Film Transistor), the liquid crystal is required to have high electrical resistance and a high voltage holding ratio (also called VHR). For this reason, fluorine- or chlorine-based liquid crystals, which have high electrical resistance and do not decrease in VHR due to active energy rays such as ultraviolet rays, are preferred.

Furthermore, the liquid crystal display element can be made into a guest-host type element by dissolving a dichroic dye in the liquid crystal composition. In this case, an element is obtained that is absorbing (scattering) when no voltage is applied and transparent when voltage is applied. In addition, in this element, the direction of the liquid crystal director (direction of orientation) changes by 90 degrees depending on whether or not voltage is applied. Therefore, this element can obtain a higher contrast than a conventional guest-host type element that switches between random orientation and vertical orientation by utilizing the difference in the light absorption characteristics of the dichroic dye. In addition, in a guest-host type element in which a dichroic dye is dissolved, the liquid crystal becomes colored when oriented horizontally and becomes opaque only in the scattering state. Therefore, it is possible to obtain an element that switches from a colored opaque state when no voltage is applied to a colored transparent state to a colorless transparent state as a voltage is applied.

The polymerizable compound in the liquid crystal composition is intended to undergo a polymerization reaction by the application of active energy rays or heat during the preparation of a liquid crystal display device to form a polymer network (also referred to as a curable resin). The polymerization reaction in the present invention is preferably one which proceeds by irradiation with ultraviolet light.
The polymerizable compound may be introduced into the liquid crystal composition in advance as a polymer obtained by subjecting the polymerizable compound to a polymerization reaction. However, from the viewpoint of handling the liquid crystal composition, i.e., preventing the liquid crystal composition from becoming highly viscous and of solubility in the liquid crystal, it is preferable to use a liquid crystal composition containing a polymerizable compound.
The polymerizable compound is not particularly limited as long as it is soluble in the liquid crystal, but when the polymerizable compound is dissolved in the liquid crystal, it is necessary that there exists a temperature at which a part or the whole of the liquid crystal composition exhibits a liquid crystal phase. Even if a part of the liquid crystal composition exhibits a liquid crystal phase, it is sufficient that the liquid crystal display element is observed with the naked eye and the entire element has substantially uniform transparency and scattering properties.

The polymerizable compound may be any compound that polymerizes when exposed to ultraviolet light or heat, and the polymerization may proceed in any reaction format to form a hardenable resin. Specific reaction formats include radical polymerization, cationic polymerization, anionic polymerization, and polyaddition reaction.

Among these, the reaction type of the polymerizable compound is preferably radical polymerization from the viewpoint of the optical characteristics of the liquid crystal display element. In this case, the following radical type polymerizable compounds or their oligomers can be used as the polymerizable compound. As described above, it is also possible to use polymers obtained by polymerizing these polymerizable compounds.

Specific examples of the radical-type polymerizable compound or an oligomer thereof include the radical-type polymerizable compounds described on pages 69 to 71 of WO 2015/146987 (published on October 1, 2015).
The proportion of the radical-type polymerizable compound or its oligomer used is preferably 70 to 150 parts by mass relative to 100 parts by mass of liquid crystal in the liquid crystal composition from the viewpoint of adhesion between the liquid crystal layer and the resin film, and more preferably 80 to 110 parts by mass. The radical-type polymerizable compound can also be used alone or in combination of two or more kinds depending on the properties.
In order to promote the radical polymerization of the polymerizable compound, it is preferable to incorporate a radical initiator (also called a polymerization initiator) that generates radicals by ultraviolet light into the liquid crystal composition.
Specific examples of the radical initiators include those described on pages 71 to 72 of International Publication WO2015/146987 (published on October 1, 2015).
The proportion of the radical initiator used is preferably 0.01 to 20 parts by mass relative to 100 parts by mass of liquid crystal in the liquid crystal composition from the viewpoint of adhesion between the liquid crystal layer and the resin film, and more preferably 0.05 to 10 parts by mass. The radical initiator may be used alone or in combination of two or more kinds depending on the properties.
<Specific liquid crystal additive compound>
It is preferable to incorporate a compound of the following formula [5a] (also referred to as a specific liquid crystal additive compound) into the liquid crystal composition.

S ¹ represents any one of the following formulas [5-a] to [5-j]. Among them, formula [5-a], formula [5-b], formula [5-c], formula [5-d], formula [5-e] or formula [5-f] is preferred. More preferred are formula [5-a], formula [5-b], formula [5-c] or formula [5-e]. Particularly preferred are formula [5-a] or formula [5-b].

S ^A represents a hydrogen atom or a benzene ring.
^S2 represents a single bond, -O-, -NH-, -N( _CH3 )-, -CH2O-, -CONH-, -NHCO-, -CON( _CH3 )-, -N( _CH3 )CO-, -COO- or -OCO-. Of these, a single bond, -O-, _-CH2O- , -CONH-, -COO- or -OCO- is preferred. A single bond, -O-, -COO- or -OCO- is _more preferred.
^S3 represents a single bond or -( _CH2 ) _a- (a is an integer of 1 to 15). Of these, a single bond or -( _CH2 ) _a- (a is an integer of 1 to 10) is preferred. -( _CH2 ) _a- (a is an integer of 1 to 10) is more preferred.
^S4 represents a single bond, -O-, -OCH ₂ -, -COO- or -OCO-. Of these, a single bond, -O- or -COO- is preferred. More preferred is -O-.
^S5 represents a divalent cyclic group selected from a benzene ring, a cyclohexane ring, and a heterocycle, or a divalent organic group having 17 to 51 carbon atoms and a steroid skeleton, and any hydrogen atom on the cyclic group may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom. Among these, a divalent organic group having 17 to 51 carbon atoms and a benzene ring or a cyclohexane ring, or a steroid skeleton is preferred. A divalent organic group having 17 to 51 carbon atoms and a benzene ring or a steroid skeleton is more preferred.
^S6 represents at least one selected from a single bond, -O-, -CH ₂ -, -OCH ₂ -, -CH ₂ O-, -COO-, and -OCO-. Of these, a single bond, -O-, -COO-, and -OCO- are preferred. A single bond, -COO-, and -OCO- are more preferred.
^S7 represents a cyclic group selected from a benzene ring, a cyclohexane ring, and a heterocycle, and any hydrogen atom on these cyclic groups may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom. Of these, a benzene ring or a cyclohexane ring is preferred.
^S8 represents an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, or a fluorine-containing alkoxy group having 1 to 18 carbon atoms. Of these, an alkyl group or alkoxy group having 1 to 18 carbon atoms, or an alkenyl group having 2 to 18 carbon atoms is preferred. An alkyl group or alkoxy group having 1 to 12 carbon atoms is more preferred.
Sm represents an integer of 0 to 4, with 0 to 2 being preferred.
The specific liquid crystal additive compound has a rigid structure such as a benzene ring or a cyclohexane ring, and a polymerizable portion represented by S ¹ in formula [5a] that undergoes a polymerization reaction by ultraviolet light or heat. Therefore, when the specific liquid crystal additive compound is included in a liquid crystal composition, the rigid structure of the specific liquid crystal additive compound enhances the vertical alignment of the liquid crystal, promotes the driving of the liquid crystal when a voltage is applied, and can reduce the driving voltage of the liquid crystal display element. In addition, the reaction of the S ¹ portion in formula [5a] with the polymerizable compound can keep the polymer network in a dense state.
More specific examples of the specific liquid crystal additive compound include the compounds of the following formulae [5a-1] to [5a-11], and it is preferable to use these compounds.

Each S ^a represents -O- or -COO-. Each S ^b represents an alkyl group having 1 to 12 carbon atoms. Each p1 represents an integer of 1 to 10. Each p2 represents an integer of 1 or 2.

Each S ^c represents a single bond, -COO- or -OCO-. Each S ^d represents an alkyl group or an alkoxy group having 1 to 12 carbon atoms. Each p3 represents an integer of 1 to 10. Each p4 represents an integer of 1 or 2.

Each S ^e represents -O- or -COO-. Each S ^f represents a divalent organic group having a steroid skeleton and having 17 to 51 carbon atoms. Each ^{S g} represents an alkyl group having 1 to 12 carbon atoms or an alkenyl group having 2 to 18 carbon atoms. Each p5 represents an integer of 1 to 10.
The proportion of the specific liquid crystal additive compound used is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the liquid crystal in the liquid crystal composition from the viewpoint of adhesion between the liquid crystal layer and the resin film. More preferably, it is 0.5 to 20 parts by mass. Particularly preferably, it is 1 to 10 parts by mass. Furthermore, the specific liquid crystal additive compound can be used alone or in combination of two or more kinds depending on the properties.
Methods for preparing the liquid crystal composition include a method of mixing liquid crystal, a polymerizable compound, and a specific liquid crystal additive compound together, and a method of mixing a polymerizable compound and a specific liquid crystal additive compound in advance and then mixing the mixture with liquid crystal.
Among them, in the present invention, a method in which a mixture of the polymerizable compound and the specific liquid crystal additive compound is mixed in advance and then mixed with the liquid crystal is preferred.
When preparing the liquid crystal composition as described above, heating may be performed depending on the solubility of the polymerizable compound and the specific liquid crystal additive compound. The temperature at that time is preferably less than 100°C.
<Method of Manufacturing Liquid Crystal Display Element>
The substrate used in the liquid crystal display element is not particularly limited as long as it is a highly transparent substrate, and in addition to a glass substrate, a plastic substrate such as an acrylic substrate, a polycarbonate substrate, or a PET (polyethylene terephthalate) substrate, or even a film thereof can be used. In particular, when used in a light control window, a plastic substrate or film is preferable. From the viewpoint of simplifying the process, it is preferable to use a substrate on which an ITO electrode, an IZO (indium zinc oxide) electrode, an IGZO (indium gallium zinc oxide) electrode, an organic conductive film, or the like for driving the liquid crystal is formed. In addition, when a reflective liquid crystal display element is used, a substrate on which a metal such as a silicon wafer or aluminum or a dielectric multilayer film is formed can be used as the substrate on only one side.
The liquid crystal display element has a resin film obtained from a resin composition containing a polymer having the specific structure (1) on at least one of the substrates. It is particularly preferable that both substrates have resin films.

The method for applying the resin composition is not particularly limited, but industrial methods include screen printing, offset printing, flexographic printing, inkjet printing, dip printing, roll coater printing, slit coater printing, spinner printing, spray printing, etc., and can be appropriately selected depending on the type of substrate and the desired thickness of the resin film.

After the resin composition is applied to the substrate, the solvent can be evaporated to form a resin film using a heating means such as a hot plate, a heat circulation oven, or an IR (infrared) oven at a temperature of 30 to 300°C, preferably 30 to 250°C, depending on the type of substrate and the solvent used in the resin composition. In particular, when a plastic substrate is used, processing at a temperature of 30 to 150°C is preferred.

If the thickness of the resin film after baking is too thick, it will be disadvantageous in terms of the power consumption of the liquid crystal display element, and if it is too thin, the reliability of the element may decrease, so the thickness is preferably 5 to 500 nm. More preferably, it is 10 to 300 nm. Especially preferably, it is 10 to 250 nm.

The liquid crystal composition used in the liquid crystal display element is the liquid crystal composition as described above, but spacers can also be introduced into it to control the electrode gap (also called the gap) of the liquid crystal display element.

The method of injecting the liquid crystal composition is not particularly limited, but examples thereof include the following methods. That is, when glass substrates are used as the substrates, a pair of substrates on which a resin film is formed is prepared, and a sealant is applied to the four pieces of one substrate, except for a portion, and then the other substrate is attached so that the resin film surface faces inward to produce an empty cell. Then, the liquid crystal composition is decompressed and injected from the place where the sealant is not applied to obtain a liquid crystal composition-injected cell. Furthermore, when plastic substrates or films are used as the substrates, a pair of substrates on which a resin film is formed is prepared, and the liquid crystal composition is dropped onto one substrate by the ODF (One Drop Filling) method or the inkjet method, and then the other substrate is attached to obtain a liquid crystal composition-injected cell.

The gap of a liquid crystal display element can be controlled by the spacers described above. Methods for this include, as described above, introducing spacers of the desired size into the liquid crystal composition, and using a substrate having column spacers of the desired size. In addition, when plastic or film substrates are used as the substrates and the substrates are bonded together by lamination, the gap can be controlled without introducing spacers.

The size of the gap in the liquid crystal display element is preferably 1 to 100 μm. More preferably, it is 1 to 50 μm. Especially preferably, it is 2 to 30 μm. If the gap is too small, the contrast of the liquid crystal display element decreases, and if it is too large, the driving voltage of the element becomes high.

A liquid crystal display element is obtained by curing a liquid crystal composition to form a liquid crystal layer while a part or the whole of the liquid crystal composition exhibits liquid crystallinity. The liquid crystal composition is cured by irradiating the liquid crystal composition-injected cell with ultraviolet light or by heating. In the present invention, as described above, irradiation with ultraviolet light is preferred.

Examples of the light source of the ultraviolet ray irradiation device used for irradiating ultraviolet rays include a metal halide lamp or a high-pressure mercury lamp. The wavelength of the ultraviolet rays is preferably 250 to 400 nm. Of these, 310 to 370 nm is preferable. After irradiation with ultraviolet rays, a heat treatment may be performed. The temperature at this time is preferably 40 to 120°C. More preferably, it is 40 to 80°C.
The heating device may be a heating means used after the resin composition is applied onto the substrate. The temperature is appropriately selected depending on the temperature at which the reaction of the polymerizable compound proceeds and the type of substrate. Specifically, 80 to 200° C. is preferable.

The present invention will be described in more detail below with reference to examples, but is not limited to these.
The abbreviations used below are as follows:
"Compounds used in polyimide polymers"
<Specific diamine (1)>

<Specific diamine (2)>

<Other diamines>

<Specific tetracarboxylic acid component>

"Compounds used in polysiloxane polymers"

E2: Octadecyltriethoxysilane E3: 3-Methacryloxypropyltrimethoxysilane E4: 3-Ureidopropyltriethoxysilane E5: Tetraethoxysilane "Cross-linking compound"

"solvent"
NMP: N-methyl-2-pyrrolidone γ-BL: γ-butyrolactone BCS: Ethylene glycol monobutyl ether PB: Propylene glycol monobutyl ether PGME: Propylene glycol monomethyl ether ECS: Ethylene glycol monoethyl ether EC: Diethylene glycol monoethyl ether "Compounds used in liquid crystal compositions"
<Specific liquid crystal additive compound>

<Polymerizable Compound>
R1: IBXA (Osaka Organic Chemical Industry Co., Ltd.)
R2: 2-hydroxyethyl methacrylate (Tokyo Chemical Industry Co., Ltd.)
R3: KAYARAD FM-400 (manufactured by Nippon Kayaku Co., Ltd.)
R4: EBECRYL 230 (manufactured by Daicel Allnex)
R5: Karenz MT PE1 (manufactured by Showa Denko)
<Photoradical initiator>
P1: IRGACURE 184 (manufactured by BASF)
<Liquid crystal>
L1: MLC-3018 (Merck)
"Molecular weight measurement of polyimide polymers"
The measurements were carried out using a room temperature gel permeation chromatography (GPC) apparatus (GPC-101) (manufactured by Showa Denko KK) and columns (KD-803, KD-805) (manufactured by Shodex KK) as follows.

Column temperature: 50 ° C.
Eluent: N,N-dimethylformamide (additives: lithium bromide monohydrate (LiBr.H ₂ O) 30 mmol/L (liter), phosphoric acid anhydrous crystal (o-phosphoric acid) 30 mmol/L, tetrahydrofuran (THF) 10 ml/L)
Flow rate: 1.0 ml/min. Standard samples for preparing a calibration curve: TSK standard polyethylene oxide (molecular weight: about 900,000, 150,000, 100,000 and 30,000) (manufactured by Tosoh Corporation) and polyethylene glycol (molecular weight: about 12,000, 4,000 and 1,000) (manufactured by Polymer Laboratory Co., Ltd.).
"Measurement of imidization rate of polyimide polymer"
20 mg of polyimide powder was placed in an NMR (nuclear magnetic resonance) sample tube (NMR sampling tube standard, φ5 (Kusano Scientific Co., Ltd.)), deuterated dimethyl sulfoxide (DMSO-d6, 0.05 mass% TMS (tetramethylsilane) mixture) (0.53 ml) was added, and the mixture was sonicated to completely dissolve. This solution was measured for proton NMR at 500 MHz using an NMR measurement device (JNW-ECA500) (JEOL Datum Co., Ltd.). The imidization rate was calculated by the following formula, using a proton derived from a structure that does not change before and after imidization as a reference proton, and the peak integrated value of this proton and the proton peak integrated value derived from the NH group of the amic acid that appears around 9.5 ppm to 10.0 ppm.

Imidization rate (%)=(1−α·x/y)×100
(x is the integrated value of the proton peak derived from the NH group of the amic acid, y is the integrated value of the peak of the reference proton, and α is the ratio of the number of the reference protons to one NH group proton of the amic acid in the case of polyamic acid (imidization rate is 0%).)
"Synthesis of polyimide polymers"
<Synthesis Example 1>
D2 (1.36 g, 5.44 mmol), A1 (1.05 g, 2.76 mmol) and C1 (1.19 g, 11.0 mmol) were mixed in NMP (10.4 g) and reacted at 80° C. for 4 hours, after which D1 (1.60 g, 8.16 mmol) and NMP (5.21 g) were added and reacted at 40° C. for 6 hours to obtain a polyamic acid solution (1) with a resin solid concentration of 25% by mass. The number average molecular weight (also referred to as Mn) of this polyamic acid was 21,500 and the weight average molecular weight (also referred to as Mw) was 64,700.
<Synthesis Example 2>
D2 (2.21 g, 8.83 mmol), A1 (1.71 g, 4.49 mmol), B1 (2.96 g, 11.2 mmol) and C1 (0.73 g, 6.75 mmol) were mixed in NMP (20.4 g) and reacted at 80° C. for 4 hours, after which D1 (2.60 g, 13.3 mmol) and NMP (10.2 g) were added and reacted at 40° C. for 6 hours to obtain a polyamic acid solution (2) with a resin solid concentration of 25% by mass. The Mn of this polyamic acid was 20,500 and the Mw was 61,000.
<Synthesis Example 3>
The polyamic acid solution (2) (20.0 g) obtained by the method of Synthesis Example 2 was diluted to 6% by mass with NMP, and then acetic anhydride (1.65 g) and pyridine (1.00 g) were added as imidization catalysts and reacted at 60° C. for 3 hours. The reaction solution was poured into methanol (450 ml), and the resulting precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 100° C. to obtain polyimide powder (3). The imidization rate of this polyimide was 55%, Mn was 18,300, and Mw was 48,300.
<Synthesis Example 4>
D4 (0.74 g, 3.73 mmol), A2 (0.75 g, 1.90 mmol), B1 (1.50 g, 5.68 mmol) and C1 (0.21 g, 1.94 mmol) were mixed in γ-BL (8.60 g) and reacted at 60° C. for 4 hours, after which D1 (1.10 g, 5.61 mmol) and γ-BL (4.30 g) were added and reacted at 40° C. for 8 hours to obtain a polyamic acid solution (4) with a resin solid concentration of 25% by mass. The Mn of this polyamic acid was 15,900 and the Mw was 47,600.
<Synthesis Example 5>
D4 (1.18 g, 5.96 mmol), A2 (0.51 g, 1.29 mmol) and B1 (1.94 g, 7.34 mmol) were mixed in γ-BL (8.25 g) and reacted at 60° C. for 4 hours, after which D1 (0.50 g, 2.55 mmol) and γ-BL (4.13 g) were added and reacted at 40° C. for 8 hours to obtain a polyamic acid solution (5) with a resin solid concentration of 25% by mass. The Mn of this polyamic acid was 13,300 and the Mw was 44,200.
<Synthesis Example 6>
D4 (0.74 g, 3.73 mmol), A3 (0.54 g, 1.25 mmol), B1 (1.66 g, 6.28 mmol) and C1 (0.54 g, 4.99 mmol) were mixed in NMP (10.4 g) and reacted at 80° C. for 4 hours, and then D1 (1.70 g, 8.67 mmol) and NMP (5.18 g) were added and reacted at 40° C. for 6 hours to obtain a polyamic acid solution (6) with a resin solid concentration of 25% by mass. The Mn of this polyamic acid was 22,300 and the Mw was 68,500.
<Synthesis Example 7>
D3 (2.00 g, 8.92 mmol), A2 (0.71 g, 1.80 mmol) and B2 (1.47 g, 7.23 mmol) were mixed in γ-BL (12.6 g) and reacted at 40° C. for 12 hours to obtain a polyamic acid solution (7) having a resin solid concentration of 25% by mass. The polyamic acid had an Mn of 14,900 and an Mw of 41,900.
<Synthesis Example 8>
D3 (2.50 g, 11.2 mmol), A4 (0.28 g, 0.57 mmol), B1 (1.79 g, 6.77 mmol) and C1 (0.43 g, 3.98 mmol) were mixed in NMP (15.0 g) and reacted at 40° C. for 12 hours to obtain a polyamic acid solution (8) with a resin solid concentration of 25% by mass. The Mn of this polyamic acid was 16,100 and the Mw was 45,200.
<Synthesis Example 9>
D2 (1.11 g, 4.44 mmol), A5 (0.84 g, 2.23 mmol), B1 (1.48 g, 5.60 mmol) and C1 (0.36 g, 3.33 mmol) were mixed in NMP (10.2 g) and reacted at 80° C. for 4 hours, and then D1 (1.30 g, 6.63 mmol) and NMP (5.10 g) were added and reacted at 40° C. for 6 hours to obtain a polyamic acid solution (9) with a resin solid concentration of 25% by mass. The Mn of this polyamic acid was 19,900 and the Mw was 60,500.
<Synthesis Example 10>
D2 (1.53 g, 6.11 mmol) and C1 (1.68 g, 15.5 mmol) were mixed in NMP (10.0 g) and reacted at 80° C. for 4 hours, and then D1 (1.80 g, 9.18 mmol) and NMP (5.01 g) were added and reacted at 40° C. for 6 hours to obtain a polyamic acid solution (10) with a resin solid concentration of 25% by mass. The Mn of this polyamic acid was 28,200 and the Mw was 73,900.
<Synthesis Example 11>
D4 (1.08 g, 5.45 mmol) and C1 (1.49 g, 13.8 mmol) were mixed in γ-BL (8.34 g) and reacted at 60° C. for 4 hours, after which D1 (1.60 g, 8.16 mmol) and γ-BL (4.17 g) were added and reacted at 40° C. for 8 hours to obtain a polyamic acid solution (11) with a resin solid concentration of 25% by mass. The Mn of this polyamic acid was 20,900 and the Mw was 58,400.
The polyimide polymers obtained in the synthesis examples are shown in Table 1.

*1: Polyamic acid.
"Synthesis of polysiloxane-based polymers"
<Synthesis Example 12>
In a 200 ml four-necked reaction flask equipped with a thermometer and a reflux condenser, ECS (28.3 g), E1 (4.10 g), E3 (7.45 g) and E5 (32.5 g) were mixed to prepare a solution of alkoxysilane monomer. A solution prepared in advance by mixing ECS (14.2 g), water (10.8 g), and oxalic acid (0.70 g) as a catalyst was added dropwise to this solution over 30 minutes at 25 ° C., and further stirred for 30 minutes at 25 ° C. Then, the mixture was heated using an oil bath and refluxed for 30 minutes, and then a mixed solution of methanol solution (1.20 g) containing 92% by mass of E4 and ECS (0.90 g) that had been previously prepared was added. After refluxing for 30 minutes, the mixture was allowed to cool to obtain a polysiloxane solution (1) with a SiO ₂ conversion concentration of 12% by mass.
<Synthesis Example 13>
In a 200 ml four-necked reaction flask equipped with a thermometer and a reflux condenser, EC (29.2 g), E1 (4.10 g) and E5 (38.8 g) were mixed to prepare a solution of an alkoxysilane monomer. A solution prepared in advance by mixing EC (14.6 g), water (10.8 g), and oxalic acid (0.50 g) as a catalyst was added dropwise to this solution over 30 minutes at 25 ° C., and further stirred for 30 minutes at 25 ° C. Then, the mixture was heated using an oil bath and refluxed for 30 minutes, and then a mixed solution of EC (0.90 g) and methanol solution (1.20 g) containing 92% by mass of E4 that had been prepared in advance was added. After refluxing for 30 minutes, the mixture was allowed to cool to obtain a polysiloxane solution (2) with a _SiO2 conversion concentration of 12% by mass.
<Synthesis Example 14>
In a 200 ml four-necked reaction flask equipped with a thermometer and a reflux condenser, ECS (28.3 g), E2 (4.07 g), E3 (7.45 g) and E5 (32.5 g) were mixed to prepare a solution of alkoxysilane monomer. A solution prepared in advance by mixing ECS (14.2 g), water (10.8 g), and oxalic acid (0.70 g) as a catalyst was added dropwise to this solution over 30 minutes at 25 ° C., and further stirred for 30 minutes at 25 ° C. Then, the mixture was heated using an oil bath and refluxed for 30 minutes, and then a mixed solution of methanol solution (1.20 g) containing 92% by mass of E4 and ECS (0.90 g) that had been prepared in advance was added. After refluxing for 30 minutes, the mixture was allowed to cool to obtain a polysiloxane solution (3) with a SiO ₂ conversion concentration of 12% by mass.

The polysiloxane polymers obtained in the synthesis examples are shown in Table 2.

"Production of resin composition"
Example 1
NMP (16.0 g) and BCS (15.7 g) were added to the polyamic acid solution (1) (10.0 g) obtained by the method of Synthesis Example 1, and the mixture was stirred at 25° C. for 6 hours to obtain a resin composition (1). This resin composition was a homogeneous solution without any abnormality such as turbidity or precipitation.
Example 2
NMP (16.0 g) and BCS (15.7 g) were added to the polyamic acid solution (2) (10.0 g) obtained by the method of Synthesis Example 2, and the mixture was stirred at 25° C. for 6 hours to obtain a resin composition (2). This resin composition was a homogeneous solution without any abnormality such as turbidity or precipitation.
Example 3
NMP (27.4 g) was added to the polyimide powder (3) (2.50 g) obtained by the method of Synthesis Example 3, and the mixture was dissolved by stirring at 70° C. for 24 hours. Then, BCS (7.83 g) and PB (3.92 g) were added, and the mixture was stirred at 25° C. for 6 hours to obtain a resin composition (3). This resin composition was a homogeneous solution without any abnormalities such as turbidity or precipitation.
Example 4
NMP (27.4 g) was added to the polyimide powder (3) (2.50 g) obtained by the method of Synthesis Example 3, and the mixture was stirred at 70° C. for 24 hours to dissolve. Then, K1 (0.13 g), BCS (7.83 g) and PB (3.92 g) were added, and the mixture was stirred at 25° C. for 6 hours to obtain a resin composition (4). This resin composition was a homogeneous solution without any abnormalities such as turbidity or precipitation.
Example 5
γ-BL (5.88 g) was added to polyimide powder (3) (2.50 g) obtained by the method of Synthesis Example 3, and dissolved by stirring at 60° C. for 24 hours. Then, PGME (33.3 g) was added and stirred at 25° C. for 6 hours to obtain resin composition (5). This resin composition was a homogeneous solution without any abnormality such as turbidity or precipitation.
Example 6
γ-BL (0.33 g) was added to the polyamic acid solution (4) (10.0 g) obtained by the method of Synthesis Example 4, and the mixture was stirred at 25° C. for 4 hours. Then, PGME (31.3 g) was added, and the mixture was stirred at 25° C. for 6 hours to obtain a resin composition (6). This resin composition was a homogeneous solution without any abnormalities such as turbidity or precipitation.
Example 7
γ-BL (0.33 g) was added to the polyamic acid solution (4) (10.0 g) obtained by the method of Synthesis Example 4, and the mixture was stirred at 25° C. for 4 hours. Then, K2 (0.18 g) and PGME (31.3 g) were added, and the mixture was stirred at 25° C. for 6 hours to obtain a resin composition (7). This resin composition was a homogeneous solution without any abnormalities such as turbidity or precipitation.
Example 8
γ-BL (0.33 g) was added to the polyamic acid solution (5) (10.0 g) obtained by the method of Synthesis Example 5, and the mixture was stirred at 25° C. for 4 hours. Then, K2 (0.13 g) and PGME (31.3 g) were added, and the mixture was stirred at 25° C. for 6 hours to obtain a resin composition (8). This resin composition was a homogeneous solution without any abnormalities such as turbidity or precipitation.
<Example 9>
To the polyamic acid solution (6) (10.0 g) obtained by the method of Synthesis Example 6, K1 (0.08 g), NMP (19.9 g) and PB (11.8 g) were added and stirred at 25° C. for 6 hours to obtain a resin composition (9). This resin composition was a homogeneous solution without any abnormality such as turbidity or precipitation.
Example 10
γ-BL (0.33 g) was added to the polyamic acid solution (7) (10.0 g) obtained by the method of Synthesis Example 7, and the mixture was stirred at 25° C. for 4 hours. Then, K2 (0.08 g) and PGME (31.3 g) were added, and the mixture was stirred at 25° C. for 6 hours to obtain a resin composition (10). This resin composition was a homogeneous solution without any abnormalities such as turbidity or precipitation.
Example 11
NMP (16.0 g), BCS (7.83 g) and PB (7.83 g) were added to the polyamic acid solution (8) (10.0 g) obtained by the method of Synthesis Example 8, and the mixture was stirred at 25° C. for 6 hours to obtain a resin composition (11). This resin composition was a homogeneous solution without any abnormality such as turbidity or precipitation.
Example 12
NMP (16.0 g) and BCS (15.7 g) were added to the polyamic acid solution (9) (10.0 g) obtained by the method of Synthesis Example 9, and the mixture was stirred at 25° C. for 6 hours to obtain a resin composition (12). This resin composition was a homogeneous solution without any abnormality such as turbidity or precipitation.
Example 13
ECS (12.5 g) and BCS (7.52 g) were added to the polysiloxane solution (1) (20.0 g) obtained by the synthesis method of Synthesis Example 12, and the mixture was stirred at 25° C. for 6 hours to obtain a resin composition (13). This resin composition showed no abnormalities such as turbidity or precipitation, and was confirmed to be a homogeneous solution.
<Example 14>
EC (8.72 g) and BCS (11.3 g) were added to the polysiloxane solution (2) (20.0 g) obtained by the synthesis method of Synthesis Example 13, and the mixture was stirred at 25° C. for 6 hours to obtain a resin composition (14). This resin composition showed no abnormalities such as turbidity or precipitation, and was confirmed to be a homogeneous solution.
Example 15
ECS (12.5 g) and BCS (7.52 g) were added to the polysiloxane solution (3) (20.0 g) obtained by the synthesis method of Synthesis Example 14, and the mixture was stirred at 25° C. for 6 hours to obtain a resin composition (15). This resin composition showed no abnormalities such as turbidity or precipitation, and was confirmed to be a homogeneous solution.
<Comparative Example 1>
NMP (16.0 g) and BCS (15.7 g) were added to the polyamic acid solution (10) (10.0 g) obtained by the method of Synthesis Example 10, and the mixture was stirred at 25° C. for 6 hours to obtain a resin composition (16). This resin composition was a homogeneous solution without any abnormality such as turbidity or precipitation.
<Comparative Example 2>
To the polyamic acid solution (11) (10.0 g) obtained by the method of Synthesis Example 11, γ-BL (0.33 g) and PGME (31.3 g) were added and stirred at 25° C. for 6 hours to obtain a resin composition (17). This resin composition was a homogeneous solution without any abnormalities such as turbidity or precipitation.
The resin compositions obtained in the examples and comparative examples are shown in Tables 3 to 5.

*2: The numbers in parentheses indicate the amount (parts by mass) of the crosslinkable compound introduced per 100 parts by mass of the polymer.
"Preparation of liquid crystal composition"
<Preparation of Liquid Crystal Composition (A)>
A polymerizable compound solution was prepared by mixing R1 (1.20 g), R2 (0.30 g), R3 (1.20 g), R4 (0.90 g) and R5 (0.30 g) and stirring for 2 hours at 60° C. Then, the prepared polymerizable compound solution, L1 (6.00 g) and P1 (0.10 g) were mixed and stirred for 6 hours at 25° C. to obtain a liquid crystal composition (A).
<Preparation of Liquid Crystal Composition (B)>
R1 (1.20 g), R2 (0.30 g), R3 (1.20 g), R4 (0.90 g) and R5 (0.30 g) were mixed and stirred at 60 ° C for 2 hours to prepare a solution of a polymerizable compound. Meanwhile, S1 (0.20 g) and L1 (5.80 g) were mixed and stirred at 25 ° C for 2 hours to prepare a liquid crystal containing a specific liquid crystal additive compound. Then, the prepared solution of the polymerizable compound, the liquid crystal containing a specific liquid crystal additive compound, and P1 (0.10 g) were mixed and stirred at 25 ° C for 6 hours to obtain a liquid crystal composition (B).
<Preparation of Liquid Crystal Composition (C)>
R1 (1.20 g), R2 (0.30 g), R3 (1.20 g), R4 (0.90 g) and R5 (0.30 g) were mixed and stirred at 60 ° C for 2 hours to prepare a solution of a polymerizable compound. Meanwhile, S2 (0.40 g) and L1 (5.60 g) were mixed and stirred at 25 ° C for 2 hours to prepare a liquid crystal containing a specific liquid crystal additive compound. Then, the prepared solution of the polymerizable compound, the liquid crystal containing a specific liquid crystal additive compound, and P1 (0.10 g) were mixed and stirred at 25 ° C for 6 hours to obtain a liquid crystal composition (C).
"Preparation of liquid crystal display elements (glass substrate)"
The resin composition obtained by the method of the above-mentioned Examples and Comparative Examples was pressure-filtered with a membrane filter having a pore size of 1 μm. The obtained solution was spin-coated on the ITO surface of a 100×100 mm glass substrate (length: 100 mm, width: 100 mm, thickness: 0.7 mm) with an ITO electrode, which had been washed with pure water and IPA (isopropyl alcohol), and then heated at 100° C. for 5 minutes on a hot plate and at 210° C. for 30 minutes in a heat circulation type clean oven to obtain an ITO substrate with a resin film having a film thickness of 100 nm. Two ITO substrates with this resin film were prepared, and a spacer having a thickness of 20 μm was applied to the resin film surface of one of the substrates. Thereafter, the liquid crystal compositions (A) to (C) were dropped on the resin film surface of the substrate coated with the spacer by the ODF (One Drop Filling) method, and then the other substrate was laminated so that the resin film surface of the other substrate faced each other, to obtain a liquid crystal display element before processing.

The untreated liquid crystal display element was irradiated with ultraviolet light for 60 seconds using a metal halide lamp with an illuminance of 20 mW/ ^cm2 , with wavelengths of 350 nm or less cut off, to obtain a liquid crystal display element (glass substrate).
"Fabrication of liquid crystal display elements (plastic substrate)"
The resin composition obtained by the method of the above-mentioned Examples and Comparative Examples was pressure-filtered with a membrane filter having a pore size of 1 μm. The obtained solution was applied by a bar coater onto the ITO surface of a 150×150 mm PET substrate (length: 150 mm, width: 150 mm, thickness: 0.1 mm) with an ITO electrode that had been washed with pure water, and the solution was heated in a heat circulation oven at 120° C. for 2 minutes to obtain an ITO substrate with a resin film having a thickness of 100 nm. Two ITO substrates with a resin film were prepared, and a spacer having a thickness of 20 μm was applied to the resin film surface of one of the substrates. Thereafter, the liquid crystal compositions (A) to (C) were dropped onto the resin film surface of the substrate on which the spacer was applied by the ODF (One Drop Filling) method, and then the other substrate was laminated so that the resin film surfaces of the substrates faced each other, to obtain a liquid crystal display element before processing. When the liquid crystal composition was dropped and laminated by the ODF method, a glass substrate was used as a support substrate for the PET substrate with an ITO electrode. Thereafter, the support substrate was removed before irradiation with ultraviolet light.

This untreated liquid crystal display element was irradiated with ultraviolet light in the same manner as in the above "Preparation of liquid crystal display element (glass substrate)" to obtain a liquid crystal display element (plastic substrate).
"Evaluation of optical properties (scattering properties and transparency)"
This evaluation was performed by measuring the haze (cloudiness) of the liquid crystal display element (glass substrate and plastic substrate) in a state where no voltage was applied (0 V) and in a state where a voltage was applied (AC drive: 10 V to 60 V). At this time, the haze was measured using a haze meter (HZ-V3, manufactured by Suga Test Instruments Co., Ltd.) in accordance with JIS K 7136. In this evaluation, it was determined that the higher the haze in the state where no voltage was applied, the better the scattering characteristics, and the lower the haze in the state where a voltage was applied, the better the transparency.

In addition, as a stability test of the liquid crystal display element in a high temperature and high humidity environment, measurements were also taken after storing it for 24 hours in a thermo-hygrostat chamber at a temperature of 80°C and a humidity of 90% RH. Specifically, the smaller the change in haze after storage in the thermo-hygrostat chamber compared to the initial haze, the better the evaluation.

Furthermore, as a stability test against light irradiation of the liquid crystal display element, observation was also performed after irradiation with ultraviolet light of 5 J/ ^cm2 converted to 365 nm using a tabletop UV curing device (HCT3B28HEX-1) (manufactured by Senlite Co., Ltd.) Specifically, the smaller the change in haze after ultraviolet light irradiation compared to the initial haze, the better the evaluation.

The results of measuring haze initially, after storage in a thermo-hygrostat (constant temperature and humidity) and after irradiation with ultraviolet light (ultraviolet light) are shown in Tables 6 to 8.
<Examples 16 to 31, Comparative Examples 3 and 4>
Using any of the resin compositions (1) to (17) obtained by the methods of the above Examples and Comparative Examples and the above liquid crystal compositions (A) to (C), liquid crystal display elements were produced and their optical properties (scattering properties and transparency) were evaluated by the above methods. In Examples 16 to 19, 25, 27, 28, 30, and Comparative Example 3, glass substrates were used to produce liquid crystal display elements and the respective evaluations were performed, while in Examples 20 to 24, 26, 29, 31, and Comparative Example 4, plastic substrates were used.

As described above, the liquid crystal display element of the Example using the resin composition containing the polymer having the specific structure (1) had a lower haze under voltage application and at a lower voltage than the Comparative Example not using the resin composition. That is, the Examples exhibited good optical properties (transparency) and the driving voltage of the liquid crystal display element was lower. Specifically, the comparison is between Example 16 and Comparative Example 3, and the comparison is between Example 21 and Comparative Example 4.
In addition, when the specific diamine (2) having the specific structure (2) was used in the polymer, the change in haze after storage in a thermo-hygrostat and after irradiation with ultraviolet light was small. Specifically, this is a comparison between Example 16 and Example 17 under the same conditions.
Furthermore, when a specific crosslinking compound was introduced into the resin composition, the change in haze after storage in a thermo-hygrostat and after UV irradiation was small. Specifically, in comparisons under the same conditions, Example 18 and Example 19, and Example 21 and Example 22 are compared.
In addition, when the liquid crystal composition containing the specific liquid crystal additive compound was used, the haze under voltage application was lower than that when the liquid crystal composition was not used, and the driving voltage was also lower. Specifically, this is a comparison between Example 22 and Example 23 under the same conditions.

By using a resin composition containing a polymer with a specific structure, a liquid crystal display element can be obtained that has good optical properties and a low driving voltage.

The liquid crystal display element of the present invention can be suitably used as a normal type element that is in a scattering state when no voltage is applied and in a transparent state when voltage is applied. This element can be used in liquid crystal displays for display purposes, and further in light control windows and light shutter elements that control the blocking and transmission of light, and a plastic substrate can be used as the substrate for this normal type element.

The entire contents of the specification, claims and abstract of Japanese Patent Application No. 2019-042708, filed on March 8, 2019, are hereby incorporated by reference as the disclosure of the specification of the present invention.

Claims (13)

A transmissive scattering type liquid crystal display element comprising: a liquid crystal layer obtained by applying at least one of active energy rays and heat to a liquid crystal composition, the liquid crystal composition including a liquid crystal and a polymerizable compound, disposed between a pair of substrates each having an electrode, and curing the liquid crystal layer; a resin film provided on at least one of the surfaces of the pair of substrates which come into close contact with the liquid crystal layer; and the transmissive scattering type liquid crystal display element being in a scattering state when no voltage is applied and in a transparent state when a voltage is applied,
The resin film is obtained using a resin composition containing a polymer having at least one structure selected from the following formulas [1-1] and [1-2] :
The liquid crystal display element is characterized in that the polymer is at least one selected from the group consisting of an acrylic polymer, a methacrylic polymer, a novolac resin, a polyhydroxystyrene, a polyimide precursor, a polyimide, a polyamide, a polyester, a cellulose, and a polysiloxane .

X ¹ represents one selected from a single bond, -(CH ₂ ) _a - (a is an integer of 1 to 15), -O-, -CH ₂ O-, -CONH-, -NHCO-, -CON(CH ₃ )-, -N(CH ₃ )CO-, -COO-, and -OCO-. X ² represents a single bond or -(CH ₂ ) _b - (b is an integer of 1 to 15). ^{X 3} represents one selected from a single bond, -(CH ₂ ) _c - (c is an integer of 1 to 15), -O-, -CH ₂ O-, -COO-, and -OCO-. ^X4 represents a divalent cyclic group selected from a benzene ring, a cyclohexane ring, and a heterocycle, or a divalent organic group having 17 to 51 carbon atoms and a steroid skeleton, and any hydrogen atom on the cyclic group may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom. ^X5 represents a cyclic group selected from a benzene ring, a cyclohexane ring, and a heterocycle, and any hydrogen atom on these cyclic groups may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxyl group having 1 to 3 carbon atoms, or a fluorine atom. Xn represents an integer of 0 to 4. ^X6 represents an alkyl group having 1 to 18 carbon atoms .

^X7 represents a single bond, -O-, _-CH2O- , -CONH-, -NHCO-, -CON( _CH3 )-, -N( _CH3 )CO-, -COO- or -OCO-, and ^X8 represents an alkyl group having 8 to 22 carbon atoms . 2. The liquid crystal display element according to claim 1, wherein the polymer further has at least one structure selected from the following formulae [2-a] to [2-i]:

Y ^A represents a hydrogen atom or a benzene ring. 3. The liquid crystal display element according to claim 1, wherein the polymer is a polyimide precursor obtained by reacting a diamine component with a tetracarboxylic acid component, or a polyimide obtained by imidizing the polyimide precursor. 4. The liquid crystal display element according to claim 3 , wherein the diamine component contains at least one diamine having a structure selected from the formulas [1-1] and [1-2]. 5. The liquid crystal display element according to claim 4 , wherein the diamine having at least one structure selected from the formulae [1-1] and [1-2] is represented by the following formula [1a]:

X represents the formula [1-1] or [1-2]. Xm represents an integer of 1 to 4. 6. The liquid crystal display element according to claim 3 , wherein the diamine component contains a diamine having a structure of the following formula [2]:

Y ¹ represents a single bond, -O-, -NH-, -N(CH ₃ )-, -CH ₂ O-, -CONH-, -NHCO-, -CON(CH ₃ )-, -N(CH ₃ )CO-, -COO- or -OCO-. Y ² represents a single bond, an alkylene group having 1 to 18 carbon atoms, or an organic group having 6 to 24 carbon atoms and having a cyclic group selected from a benzene ring, a cyclohexane ring and a heterocycle, and any hydrogen atom on the cyclic group may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms or a fluorine atom. ^Y3 represents one type selected from a single bond, -O-, -NH-, -N( _CH3 )-, -CH2O-, _-CONH- , -NHCO-, -CON( _CH3 )-, -N( _CH3 )CO-, -COO- and -OCO-. ^Y4 represents one type of structure selected from formulae [2-a] to [2-i]. Yn represents an integer of 1 to 4. 7. The liquid crystal display element according to claim 6 , wherein the diamine having the structure of the formula [2] is the following formula [2a]:

Y represents the structure of the above formula [2]. Ym represents an integer of 1 to 4. 8. The liquid crystal display element according to claim 3 , wherein the tetracarboxylic acid component contains a tetracarboxylic dianhydride represented by the following formula [3]:

Z represents any one of the following formulas [3a] to [3l].

Z ^A to Z ^D each represents a hydrogen atom, a methyl group, a chlorine atom or a benzene ring, and Z ^E and Z ^F each represent a hydrogen atom or a methyl group. 3. The liquid crystal display element according to claim 1, wherein the polymer comprises a polysiloxane obtained by polycondensing an alkoxysilane represented by the following formula [A1], or a polysiloxane obtained by polycondensing the alkoxysilane represented by the formula [A1] with an alkoxysilane represented by the following formula [A2] and /or formula [A3]:

^A1 represents the formula [1-1] or [1-2]. ^A2 represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. ^A3 represents an alkyl group having 1 to 5 carbon atoms. m represents an integer of 1 or 2. n represents an integer of 0 to 2. p represents an integer of 0 to 3. However, m+n+p is 4.

^B1 represents an organic group having 2 to 12 carbon atoms and having at least one group selected from a vinyl group, an epoxy group, an amino group, a mercapto group, an isocyanate group, a methacryl group, an acryl group, a ureido group, and a cinnamoyl group. ^B2 represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. ^B3 represents an alkyl group having 1 to 5 carbon atoms. m represents an integer of 1 or 2. n represents an integer of 0 to 2. p represents an integer of 0 to 3, with the proviso that m+n+p is 4.

^D1 represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. ^D2 represents an alkyl group having 1 to 5 carbon atoms. n represents an integer of 0 to 3. 10. The liquid crystal display element according to claim 1, wherein the liquid crystal composition contains a compound represented by the following formula [5a]:

S ¹ represents any one of the following formulae [5-a] to [5-j]. S ² represents a single bond, -O-, -NH-, -N(CH ₃ )-, -CH ₂ O-, -CONH-, -NHCO-, -CON(CH ₃ )-, -N(CH ₃ )CO-, -COO-, or -OCO-. S ³ represents a single bond or -(CH ₂ ) _a - (wherein a is an integer of 1 to 15). ^{S 4} represents a single bond, -O-, -OCH ₂ -, -COO-, or -OCO-. S ⁵ represents a divalent cyclic group selected from a benzene ring, a cyclohexane ring, and a heterocycle, or a divalent organic group having 17 to 51 carbon atoms and a steroid skeleton, and any hydrogen atom on the cyclic group may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom. S ⁶ represents a single bond, -O-, -CH ₂ -, -OCH ₂ -, -CH ₂ O-, -COO-, or -OCO-. S ⁷ represents a cyclic group selected from a benzene ring, a cyclohexane ring, and a heterocycle, and any hydrogen atom on these cyclic groups may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom. ^S8 represents an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, or a fluorine-containing alkoxy group having 1 to 18 carbon atoms. Sm represents an integer of 0 to 4.

S ^A represents a hydrogen atom or a benzene ring. 11. The liquid crystal display element according to claim 10 , wherein the compound of the formula [5a] is any one of the following formulas [5a-1] to [5a-11]:

Each S ^a represents -O- or -COO-. Each S ^b represents an alkyl group having 1 to 12 carbon atoms. Each p1 represents an integer of 1 to 10. Each p2 represents an integer of 1 or 2.

Each S ^c represents a single bond, -COO- or -OCO-. Each S ^d represents an alkyl group or an alkoxy group having 1 to 12 carbon atoms. Each p3 represents an integer of 1 to 10. Each p4 represents an integer of 1 or 2.

Each S ^e represents -O- or -COO-. Each S ^f represents a divalent organic group having a steroid skeleton and having 17 to 51 carbon atoms. Each ^{S g} represents an alkyl group having 1 to 12 carbon atoms or an alkenyl group having 2 to 18 carbon atoms. Each p5 represents an integer of 1 to 10. The liquid crystal display element according to any one of claims 1 to 11, wherein the resin composition further comprises a crosslinkable compound having at least one selected from an epoxy group, an isocyanate group, an oxetane group, a cyclocarbonate group, a hydroxy group, a hydroxyalkyl group, and a lower alkoxyalkyl group. 13. The liquid crystal display element according to claim 1, wherein a substrate of the liquid crystal display element is a glass substrate or a plastic substrate.