NOVEL CROSSLINKER, CURABLE COMPOSITION, PREPREG, LAMINATE, METAL-CLAD LAMINATE AND CIRCUIT BOARD

To provide a crosslinker that is suitable for a curable composition and is capable of giving a (semi)cured product having a dielectric loss tangent (Df) effectively reduced under high frequency conditions, having a sufficiently low thermal expansion coefficient (CTE), and having a sufficiently high glass transition temperature (Tg).SOLUTION: A crosslinker is represented by the formula (X) (where A is a Group 14 element selected from the group consisting of Ge, Sn, and Pb, L is a single bond, an aromatic ring, a C1-20 alkylene group, or a combination of a C1-20 alkylene group and an aromatic ring. n is an integer of 2-4. R is a hydrogen atom, a hydroxy group, or an organic group, and if R is an organic group, the atom bound to A is C).SELECTED DRAWING: Figure 1 【課題】硬化性組成物に用いて好適で、高周波条件における誘電正接（Ｄｆ）が効果的に低減され、熱膨張係数（ＣＴＥ）が充分に低く、ガラス転移温度（Ｔｇ）が充分に高い（半）硬化物を得ることが可能な架橋剤。【解決手段】下式（Ｘ）で表される架橋剤。TIFF2023105332000015.tif56127（上式中、Ａは、Ｇｅ、ＳｎおよびＰｂからなる群より選ばれる１４族元素、Ｌは単結合、芳香環、炭素数１～２０のアルキレン基、または、炭素数１～２０のアルキレン基と芳香環との組合せ。ｎは２～４の整数。Ｒは水素原子、水酸基または有機基であり、Ｒが有機基であるとき、Ａと結合した原子はＣ。）【選択図】図１